A 19-year-old University of Michigan student was found dead Saturday after he was reported missing the day before during a stretch of dangerously cold weather, authorities said. The sophomore, identified by officials as Lucas Mattson, was last seen around 1 a.m. Friday after leaving a gathering near campus wearing a T-shirt and jeans as temperatures hovered near zero.
Ann Arbor police said a nearly 20-hour search followed, with city officers and university public safety units canvassing neighborhoods and using a drone unit in “extreme cold conditions.” Mattson’s body was located around midday Saturday in the 1900 block of Cambridge Road, a residential area not far from where he was last seen. Detectives said there were no obvious signs of trauma and that foul play is not suspected at this stage. The Washtenaw County Medical Examiner’s Office will conduct an autopsy to determine an official cause and manner of death in the coming days.
Police received the missing-person report Friday afternoon after friends and relatives were unable to reach Mattson. Investigators retraced his movements from the early morning, gathering surveillance footage and witness accounts that placed him walking alone without a coat as wind chills cut through side streets. Officers and campus safety personnel spread out across nearby blocks, checked alleyways and construction zones, and searched green spaces where snow had drifted. By nightfall, search teams focused on corridors leading from the party location toward residential streets east of central campus. The discovery on Cambridge Road came just after noon Saturday, when responders converged on the block and cordoned off the area.
Officials identified Mattson as a sophomore in the College of Engineering. University leaders expressed condolences and said support services were available to students and staff affected by the loss. In a campus message, administrators warned against speculation as detectives await medical findings. Police emphasized that early reviews of the scene and collected video did not point to an assault or vehicle strike. Officers documented footprints, clothing impressions and snow conditions along the route where he was believed to have walked, noting frigid temperatures that persisted through Friday and into Saturday.
The search unfolded during a week of severe winter weather across Michigan tied to a broader storm system that pushed wind chills below zero in Ann Arbor. City services had been clearing primary roads while side streets remained icy, and emergency calls spiked for weather-related issues. Police said those conditions guided how teams deployed Friday night, with shifts rotating to limit exposure and to preserve battery life for drones and radios. Responders checked vacant lots and recessed entryways along residential blocks where drifting snow can conceal hazards, then widened the grid outward from the last confirmed sighting.
Detectives are assembling a timeline beginning with Mattson’s departure from the gathering shortly after 1 a.m. Friday. Investigators said he was reported missing roughly 15 hours later, triggering the larger, coordinated search. Officers interviewed partygoers and residents who might have seen him on foot, reviewed doorbell-camera clips and requested store surveillance from nearby corridors. Authorities did not publicly list the exact temperature at the time he was last seen, but officials described the conditions as “extreme cold” overnight, with wind and refreezing that made walking treacherous on untreated surfaces.
Neighbors on Cambridge Road described a heavy response late Saturday morning as patrol cars and a mobile command vehicle arrived. Crime scene technicians photographed the area and took measurements while detectives spoke with residents who had provided footage from the prior day. The street, lined with homes set back from the curb, had plowed snow berms and patches of ice along the sidewalks. Officers placed evidence markers near a plowed edge and along a walkway leading toward the house fronts, then removed items for laboratory review.
Police said the medical examiner would consider environmental exposure among other possibilities. Autopsy and toxicology results typically take several weeks, and investigators said any findings relevant to the public would be released when available. Authorities declined to discuss whether Mattson had communicated with anyone after leaving the gathering or whether his phone provided usable location data. As of Tuesday, officers said their review had uncovered no indication of a confrontation, collision or other third-party involvement.
In separate remarks, university officials said they would review campus communications and late-night transportation options in the area to understand how Friday’s events progressed and whether any operational changes are warranted. Counseling and Psychological Services expanded availability for students, and residence hall staff were briefed on resources. The engineering college dean said faculty would work with students affected by the loss to adjust coursework as needed in the short term.
Friends described Mattson as a thoughtful classmate with a strong interest in design and a close circle on his residence hall floor. Informal memorials appeared near a walkway off Cambridge Road by Sunday, with flowers and handwritten notes placed in the snow. On social media, peers shared photographs from study groups and weekend outings and wrote messages to his family. City leaders also issued condolences, noting that first responders from multiple agencies took part in the search effort through the coldest hours of the week.
Police asked anyone with information about Mattson’s movements between 1 a.m. and late Friday morning to contact the department to assist in finalizing the timeline, a standard step in death investigations even when foul play is not suspected. Detectives said they would compile a final report after the autopsy and evidence reviews are complete. Results from the medical examiner are expected to clarify whether exposure was the primary factor or whether another medical condition contributed.
As of Wednesday, investigators said the case remains open pending the medical examiner’s findings. Officials said a further update will follow once autopsy and toxicology results are returned and the investigative timeline is complete.
Author note: Last updated January 28, 2026.