United Airlines Flight 223 was diverted to Denver International Airport this afternoon after a passenger attempted to open an exterior door in mid-air.

Just after 5 p.m., the plane landed safely at DIA. The plane had been traveling from Washington Dulles International Airport to Las Vegas, according to DIA spokesman Jeff Green.

“It’s virtually impossible to open an exterior door while in flight,” Green said.

The disturbance began around 4:45 p.m., Charlie Hobart, United spokesman said.

United is cooperating with authorities, who were waiting for the suspect at the gate, Hobart said.

The man had consumed alcohol before and during the flight, Kathy Wright FBI spokeswoman said. After questioning at DIA the suspect was sent for a medical evaluation.

Next week investigators will determine whether charges will be filed.

“Instances like these usually involve some type of interference with the fight crew, which is a felony,” Wright said.