The man who was fatally struck on Friday by a departing Frontier Airlines flight on the runway of Denver international airport died by suicide, the city’s medical examiner said Tuesday at a news conference.

On Friday evening, the man, identified as 41-year-old Michael Mott, jumped an 8-ft fence with barbed wire onto the runway, according to Phillip Washington, the airport’s chief executive. Roughly 2 mins lapsed between Mott’s breach of the runway and when he was hit by the Frontier aircraft.

Mott was not an airport employee. He had previous contact with metropolitan-area law enforcement, said Ron Thomas, the Denver police chief. It’s unclear what the contact entailed.

The determination of Mott’s manner of death was based on an investigation and scene findings, said Sterling McLaren, a medical examiner. Mott suffered “multiple blunt and sharp force injuries”.

Friday’s deadly collision has raised questions about the airport’s security.

“After the incident, we examined the fence, as we do on a regular basis, and found it to be intact,” Washington said. The airport’s perimeter fencing spans 36 miles.

Ground detection sensors set off an alarm near where Mott scaled the fence. An investigator reviewing the alarm identified a herd of deer, but did not initially see Mott, according to Washington.

“The camera view was alternating between the wildlife and the individual,” Washington said. “Given the short time period, we were not able to intervene and prevent this person from reaching the runway.”

The airport is not considering electrifying the fence or making it taller. “We believe a motivated individual could find a way to penetrate it,” he said.

Asked by a reporter about changes to the perimeter security, Washington said “we will look to see what improvements we can make”.

The Transportation Security Administration sets guidance about the dimension and heights of airport fencing, which Washington said the airport has adhered to.

Washington touted the track record of the airport’s current “layered” security plan, which involves patrols and technology. There have been previous fence jumpers, he said, but an exact estimate was not provided.

Thomas said law enforcement is looking for individuals that knew Mott and evaluating whether mental health issues factored into his actions.

It’s unclear how Mott reached the fence. Police did not find a vehicle or bicycle in the surrounding farmland area on the airport’s eastern perimeter.

Frontier flight 4345, bound for Los Angeles international airport, was carrying 224 passengers and seven crew members. Mott was pulled into the aircraft’s engine, sparking a fire and the evacuation of the plane.

Smoke reportedly poured into the air cabin, making it difficult for some passengers to breathe.

Twelve individuals on board reported minor injuries, according to Washington. Five people were transported to local hospitals, four of whom have since been released.

Addressing the passengers, Washington said: “I want to acknowledge what a difficult and scary experience you had.”