Campus Alert Archive
U-M

All clear after Mason Hall unconfirmed active shooter report

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Confirmed HoaxDetermined to be a hoax. The institutional response is documented because it reveals how the alert system performed under a perceived real threat.

University of Michigan DPSS published this notice. Full text is preserved from the official DPSS news page.

Alerts
1
Response
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Killed
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Injured
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Institution
University of Michigan
Public R1 · MI
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~51,000 studentsDPSS / U-M Emergency Alert
Official alert policy
Read when and how U-M says it will use U-M Emergency Alert: summarized, quoted, and analyzed.
Documented Timeline

Alert Sequence

1 message in sequence · 1 verified verbatim

Confirmed wording is transcribed character-for-character from a primary source. Use Verify this quote under each message to open that source in a new tab and compare the text yourself.

ALL CLEARMulti-channel
Verified verbatim791 chars
All Clear: 7:50 p.m. Police have determined there is no threat to the community. Buildings are open. All clear. Update #3: 6:35 p.m. There continues to be no indication of an active threat to the community. Police continue to investigate. Please stay away from Angell and Mason Halls. Update #2: 5:32 p.m. There does not appear to be an active threat to the community. DPSS continues to investigate. Continue to stay clear of area. Update #1: 5:17 p.m. Unconfirmed reports of an active shooter, officers are in the area checking. Stay away from the area of Mason Hall. UM-Ann Arbor EAlert: 4:40 p.m. Active shooter in Mason Hall. Run. Hide. Fight.™ www.dpss.umich.edu. For more information about this event visit: https://publicaffairs.vpcomm.umich.edu/unfounded-reports-of-shots-fired/
Verify this quote
U-M DPSS news / emergency alert pagedpss.umich.edufind archived copies
Transcribed from official news.dpss.umich.edu post HTML.
First-message queue 2026-08-16: first preserved official artifact is the DPSS compiled notice. It embeds the original 4:40 p.m. EAlert (active shooter Mason Hall / run hide fight) plus updates and the 7:50 p.m. all-clear. Typed all-clear because the published page is the all-clear compilation. No separate earlier official page in this seam.
2026-09-21 second deep audit b49 P3 partial: multi-update-flatten. Recapture live dpss.umich.edu rich-text p-tags. h1 and Emergency Alert Overview h2 are page chrome. Original EAlert is Run. Hide. Fight.™ Dual p. Cap-exempt R1. Official compiled notice kept as the page product.
Message elements

How the first alert is built

To check this alert, Claude Opus 5.5 (an AI) read it in full 25 separate times, independently. Each read decided whether the message answers each of the six questions and gave a short reason. A final reviewer then weighed all 25 and wrote the plain-English verdict you see when you open a row. The score (for example 22/25) is how many reads agreed; the 25 individual reads are tucked underneath if you want to check them.

All Clear: 7:50 p.m. Police have determined there is no threat to the community. Buildings are open. All clear. Update #3: 6:35 p.m. There continues to be no indication of an active threat to the community. Police continue to investigate. Please stay away from Angell and Mason Halls. Update #2: 5:32 p.m. There does not appear to be an active threat to the community. DPSS continues to investigate. Continue to stay clear of area. Update #1: 5:17 p.m. Unconfirmed reports of an active shooter, officers are in the area checking. Stay away from the area of Mason Hall. UM-Ann Arbor EAlert: 4:40 p.m. Active shooter in Mason Hall. Run. Hide. Fight.™ www.dpss.umich.edu. For more information about this event visit: https://publicaffairs.vpcomm.umich.edu/unfounded-reports-of-shots-fired/

  • Sourcepresent25/25

    Final assessment

    All 25 reads agree the source is present: the "UM-Ann Arbor EAlert" tag, plus mentions of DPSS and police, identify the sender.

    Who is sending the alert and who is responding. People act faster on a message from a clearly identifiable, credible sender, such as a named department, the police, or a branded alert system, than on an anonymous notice. A branded signature counts.

    See all 25 individual reads
    1. present: It carries the 'UM-Ann Arbor EAlert' tag and names DPSS and police.
    2. present: 'UM-Ann Arbor EAlert' and DPSS are named.
    3. present: The branded 'UM-Ann Arbor EAlert' and DPSS identify the sender.
    4. present: 'UM-Ann Arbor EAlert' and DPSS.
    5. present: It uses the 'UM-Ann Arbor EAlert' tag and names DPSS.
    6. present: The tag "UM-Ann Arbor EAlert" and DPSS identify the sender.
    7. present: Branded 'UM-Ann Arbor EAlert' and cites DPSS.
    8. present: It includes "UM-Ann Arbor EAlert" and names DPSS and police.
    9. present: The tag "UM-Ann Arbor EAlert" and DPSS identify the sender.
    10. present: It carries the tag 'UM-Ann Arbor EAlert' and names DPSS.
    11. present: The tag "UM-Ann Arbor EAlert" and DPSS identify the sender.
    12. present: It carries the "UM-Ann Arbor EAlert" tag and names DPSS.
    13. present: The tag "UM-Ann Arbor EAlert" and DPSS identify the sender.
    14. present: It carries the UM-Ann Arbor EAlert tag and names DPSS.
    15. present: 'UM-Ann Arbor EAlert' and DPSS are named.
    16. present: "UM-Ann Arbor EAlert" and DPSS identify the sender.
    17. present: The tag 'UM-Ann Arbor EAlert' and police identify the sender.
    18. present: It carries 'UM-Ann Arbor EAlert' and names DPSS.
    19. present: Branded 'UM-Ann Arbor EAlert' with DPSS and police.
    20. present: UM-Ann Arbor EAlert and DPSS.
    21. present: 'UM-Ann Arbor EAlert' and DPSS identify the sender.
    22. present: It includes 'UM-Ann Arbor EAlert' and names DPSS.
    23. present: It carries the tag 'UM-Ann Arbor EAlert' and names DPSS.
    24. present: It carries the "UM-Ann Arbor EAlert" tag and names DPSS.
    25. present: It carries the tag 'UM-Ann Arbor EAlert' and references DPSS and police.
  • Hazardpresent25/25

    Final assessment

    Unanimous: the first message names an "Active shooter in Mason Hall", a specific hazard.

    What the threat actually is. A complete warning names the specific danger, such as a shooter, a fire, a tornado, or a gas leak, rather than a vague emergency, because people decide what to do based on what they are facing.

    See all 25 individual reads
    1. present: It names an 'Active shooter in Mason Hall'.
    2. present: It names an active shooter.
    3. present: It names an 'Active shooter'.
    4. present: Active shooter.
    5. present: It names an 'Active shooter in Mason Hall'.
    6. present: It names an "Active shooter".
    7. present: Names an active shooter.
    8. present: It names an "Active shooter in Mason Hall".
    9. present: It names an "Active shooter".
    10. present: It names an 'Active shooter in Mason Hall'.
    11. present: It names an "Active shooter".
    12. present: It names an active shooter.
    13. present: It names an active shooter.
    14. present: It names an active shooter.
    15. present: Names 'Active shooter'.
    16. present: It names an "Active shooter".
    17. present: It names an active shooter.
    18. present: It names an active shooter.
    19. present: Names 'Active shooter in Mason Hall'.
    20. present: Active shooter.
    21. present: It names an active shooter.
    22. present: It names 'Active shooter'.
    23. present: It names an 'Active shooter'.
    24. present: It names an "Active shooter".
    25. present: The first alert says 'Active shooter in Mason Hall', a specific threat.
  • Locationpresent25/25

    Final assessment

    All reads agree the location is specific: Mason Hall and Angell Hall are named.

    Where the threat is. Saying whether danger is in a specific building, a part of campus, or area-wide lets people judge their own proximity and choose a safe direction. Without a where, a warning is hard to act on precisely.

    See all 25 individual reads
    1. present: It names Mason Hall and Angell Hall.
    2. present: It names Mason Hall and Angell Hall.
    3. present: It names Mason Hall and Angell Hall.
    4. present: Mason Hall and Angell Hall.
    5. present: It gives 'Mason Hall' and 'Angell and Mason Halls'.
    6. present: It specifies "Mason Hall" and "Angell and Mason Halls".
    7. present: Gives Mason Hall and Angell Hall.
    8. present: It names Mason Hall and Angell Hall.
    9. present: It gives Mason Hall and Angell Hall.
    10. present: It names 'Mason Hall' and 'Angell and Mason Halls'.
    11. present: It names Mason Hall and Angell Hall.
    12. present: It specifies Mason Hall and Angell Hall.
    13. present: It names Mason Hall and Angell Hall.
    14. present: It names Mason Hall and Angell Hall.
    15. present: 'Mason Hall'.
    16. present: It gives "Mason Hall" and "Angell and Mason Halls".
    17. present: It gives Mason Hall and Angell Hall.
    18. present: It names Mason Hall and Angell Hall.
    19. present: Mason Hall and Angell Hall.
    20. present: Mason Hall and Angell Hall.
    21. present: It names Mason Hall and Angell Hall.
    22. present: It gives 'Mason Hall' and 'Angell'.
    23. present: It names Mason Hall and Angell Hall.
    24. present: It names Mason Hall and Angell Hall.
    25. present: It names 'Mason Hall' and 'Angell and Mason Halls'.
  • Guidancepresent25/25

    Final assessment

    Unanimous: recipients are told "Run. Hide. Fight." and to "Stay away from the area of Mason Hall".

    The protective action to take. A clear, specific instruction, such as shelter in place, evacuate, avoid the area, or run-hide-fight, drives faster and more correct protective behavior than describing the threat alone.

    See all 25 individual reads
    1. present: It instructs 'Run. Hide. Fight.' and 'Stay away from the area of Mason Hall'.
    2. present: It says 'Run. Hide. Fight.' and 'stay away'.
    3. present: It instructs 'Run. Hide. Fight.' and to stay away from the area.
    4. present: 'Run. Hide. Fight.' and stay away.
    5. present: It instructs 'Run. Hide. Fight.' and 'Stay away from the area of Mason Hall'.
    6. present: It instructs "Run. Hide. Fight." and "Stay away from the area".
    7. present: Says 'Run. Hide. Fight.' and stay away from the area.
    8. present: It says "Run. Hide. Fight." and to stay away from the area.
    9. present: It says "Run. Hide. Fight." and to stay away.
    10. present: It says 'Run. Hide. Fight.' and 'Stay away from the area'.
    11. present: It instructs "Run. Hide. Fight." and "Stay away".
    12. present: It says "Run. Hide. Fight." and to stay away from the area.
    13. present: It says "Run. Hide. Fight." and stay away from the area.
    14. present: It says Run. Hide. Fight. and to stay away from the area.
    15. present: 'Run. Hide. Fight.' and 'stay away'.
    16. present: It says "Run. Hide. Fight." and "Stay away from the area".
    17. present: It says 'Run. Hide. Fight.' and to stay away from the area.
    18. present: It says 'Run. Hide. Fight.' and 'Stay away from the area'.
    19. present: 'Run. Hide. Fight.' and 'Stay away from the area of Mason Hall'.
    20. present: Run. Hide. Fight. and stay away from the area.
    21. present: It says 'Run. Hide. Fight.' and to stay away.
    22. present: It says 'Run. Hide. Fight.' and 'Stay away from the area'.
    23. present: It says 'Run. Hide. Fight.' and 'stay away from Angell and Mason Halls'.
    24. present: It says "Run. Hide. Fight." and "Stay away" from the area.
    25. present: It instructs 'Run. Hide. Fight.' and 'Stay away from the area of Mason Hall'.
  • Timepresent25/25

    Final assessment

    All 25 reads find timing present: each post carries a clock time, from "4:40 p.m." through "7:50 p.m.".

    When the message applies. A timestamp, the word now or immediately, or a phrase like until further notice tells the reader whether the danger is current and how quickly to act.

    See all 25 individual reads
    1. present: Each post has a clock time, from '4:40 p.m.' to '7:50 p.m.'.
    2. present: It gives times such as 4:40 p.m. and 7:50 p.m.
    3. present: Each entry has a clock time such as 4:40 p.m.
    4. present: Clock times 4:40 to 7:50 p.m.
    5. present: Each message carries a clock time such as '4:40 p.m.' and '7:50 p.m.'.
    6. present: Each update carries a clock time such as "4:40 p.m." and "7:50 p.m."
    7. present: Gives times such as 4:40 p.m. and 7:50 p.m.
    8. present: Each entry has a clock time, from 4:40 p.m. to 7:50 p.m.
    9. present: It gives times such as 4:40 p.m. and 7:50 p.m.
    10. present: It gives times such as '4:40 p.m.' and '7:50 p.m.'.
    11. present: Each message carries clock times like 4:40 p.m. and 7:50 p.m.
    12. present: It gives times from 4:40 p.m. to 7:50 p.m.
    13. present: Each message carries a clock time such as 4:40 p.m.
    14. present: It gives clock times from 4:40 p.m. to 7:50 p.m.
    15. present: Clock times such as '4:40 p.m.'.
    16. present: It gives clock times like "4:40 p.m." and "7:50 p.m.".
    17. present: It gives times such as 4:40 p.m. and 7:50 p.m.
    18. present: It gives times such as 4:40 p.m. and 7:50 p.m.
    19. present: Clock times from 4:40 p.m. to 7:50 p.m.
    20. present: 4:40 p.m. through 7:50 p.m.
    21. present: Each update has a clock time such as 4:40 p.m.
    22. present: Each post has a clock time such as '4:40 p.m.' and '7:50 p.m.'.
    23. present: It gives times from 4:40 p.m. to 7:50 p.m.
    24. present: Each message has a clock time such as 4:40 p.m. and 7:50 p.m.
    25. present: Each message is timestamped, from '4:40 p.m.' through the '7:50 p.m.' all clear.
  • Impactabsent0/25

    Final assessment

    All 25 reads agree impact is absent: beyond naming an active shooter, no consequence or severity is stated, and the updates say there is "no threat".

    What the hazard could do to the people in its path. Beyond naming the threat, a complete warning conveys its potential consequences or severity, such as that a tornado can level buildings or that a leak could be explosive, so recipients grasp how much danger they are in. Research on warning message content finds that a concrete impact statement helps people personalize their risk and act sooner.

    See all 25 individual reads
    1. absent: Updates say there is 'no threat'; no consequence or severity is stated.
    2. absent: No consequence or severity is stated.
    3. absent: No consequence or severity statement appears.
    4. absent: No stated consequence.
    5. absent: No consequence or severity is stated beyond naming the hazard.
    6. absent: No statement of consequence or severity appears.
    7. absent: No consequence or severity is stated.
    8. absent: No consequence or severity is stated beyond naming the hazard.
    9. absent: No consequence is stated; later updates say there is no threat.
    10. absent: It names the hazard but never states its potential harm or severity.
    11. absent: No consequence is stated and later messages say no threat.
    12. absent: It states no consequence and ends saying there is no threat.
    13. absent: No consequence or severity is stated.
    14. absent: No consequence or severity is stated.
    15. absent: No consequence or severity is stated.
    16. absent: No consequence or severity is stated beyond the hazard name.
    17. absent: No consequence or severity is stated beyond naming the hazard.
    18. absent: It names the hazard but states no consequence or severity.
    19. absent: No consequence or severity statement beyond naming the hazard.
    20. absent: No consequence or severity stated.
    21. absent: No consequence or severity is stated.
    22. absent: No consequence or severity is stated.
    23. absent: It states no consequence and ends with 'no threat to the community'.
    24. absent: No consequence or severity is stated, and later it says no threat.
    25. absent: It names the active shooter and later finds 'no threat', but never states consequences like injuries or danger to life.

Coded by Claude Opus 5.5

Systematic AI judgments with visible reasoning, not human-validated codings.

About this analysis
Context

Background

University of Michigan DPSS news.dpss.umich.edu official notice archive.
Analysis

Key Findings

Official DPSS notice provides full transmitted alert or security bulletin text.
Outcome
See official DPSS notice for investigation status and community guidance.
Provenance

Sources

Every claim on this page is meant to be checkable. Open the links below (and the Verify this quote control under each confirmed alert) to read the original university, news, or archive page yourself. Hostnames are shown so you can see where you are going; archived copies survive when live pages move or disappear. See also our methodology.

  1. Official
    UM EMERGENCY ALERT – ALL CLEAR
    dpss.umich.edu
    archived copy
Cite this case

Campus Alert Archive. "University of Michigan: All clear after Mason Hall unconfirmed active shooter report." Incident of March 16, 2019. Added July 2026; last updated September 2026. https://campusalertarchive.com/case/university-of-michigan-mason-hall-active-shooter-all-clear-2019-03-16/

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Alert text quoted on this page remains the work of the issuing institution; the archive is a secondary source.

Tags
michigandpssswattingemergency-alertHoax
Added July 2026Updated September 2026Via ingestion