NORTHGLENN, Colo. -- A Broomfield man was killed and at least three others injured in a fatal chain-reaction crash involving 10 vehicles on Interstate 25 Monday night.

Northglenn police said the crash occurred just after 7 p.m., when a gray Jeep Liberty got on to northbound I-25 going the wrong way and slammed head-on into a white Ford F-150 pickup truck. That truck was pulling a trailer with another vehicle on top of it. The trailer came off and smashed several vehicles, Northglenn police Sgt. Rick Kellogg said.

The Jeep Liberty continued southbound -- crashing into several more vehicles -- before it stopped at the center median.

The male driver of the Liberty was pronounced dead at the scene. He was identified as 48-year-old David S. Ulwelling. Police don't know yet what caused him to go the wrong way on I-25. Witnesses told police that he entered I-25 by using the northbound RTD bus offramp that goes under I-25 around 117th Avenue.

The toxicology reports, which will determine whether Ulwelling had drugs or alcohol in his system, won't be completed for 10 to 14 days, Northglenn police said.

Three other people were taken to the hospital after the crash. Their names weren't released but they were all released by Tuesday afternoon. They suffered minor injuries.

Car parts were strewn for about 100 feet down the interstate.

Northbound I-25 at 104th Avenue was closed until shortly before midnight.

Anyone who witnessed this incident is asked to call the Northglenn police accident team at 303-450-8893.