MARQUETTE, Mich. (WLUK) — The search for a missing U.P. college student is over, law enforcement announced Wednesday.

Northern Michigan University student Trenton Massey, 21, disappeared early Sunday morning. In the days since he was reported missing, more than a dozen agencies, as well as countless volunteers, have aided in the search, but Massey has not been recovered.

On Wednesday afternoon, the Marquette Police Department said search efforts have been suspended, but an investigation remains ongoing.

The case began around 8 a.m. Sunday, when Massey’s cell phone was turned in to police. It had been found on a multi-use path in the city of Marquette. A family member of Massey’s was contacted, and they said they would notify Massey his phone had been found. But later that day, the family member alerted police that Massey had not been heard from and was believed to be missing.

Surveillance cameras captured Massey in the downtown Marquette area around 2:50 a.m. Sunday, traveling eastbound on the path where his phone was discovered. Additional footage showed Massey heading to the Founder’s Landing Boardwalk around 3:25 a.m. Authorities say he appeared to be “disoriented” and “having difficulty walking.”

Shortly after 3:30 a.m., Massey was seen walking out onto the ice from the north Founder’s Landing Pier. He then disappeared from the view of the camera. The NMU campus was closed Monday due to a winter storm.

Specialized equipment has been used to search on land, in the water and from the air, including a helicopter, airboat, underwater remote-operated vehicle, sonar units, scuba divers, drones, K9s and a hover craft.