Denver police are investigating a fiery six-vehicle crash that killed a driver and seriously injured two people in the city’s Sunnyside neighborhood Monday morning.

Officers at the expansive scene near the intersection of 44th Avenue and Federal Boulevard — spread over roughly a city block — cordoned off the area in red and yellow caution tape.

Police say they have arrested a man in connection with the wreck but declined to release his name Monday.

A witness told The Denver Post he saw the driver and a passenger of a Jeep Wrangler caught in flames after the SUV was involved in the crash and a subsequent explosion. The fiery wreck happened about 6:30 a.m., shutting down some traffic in the area.

“He passed by one of our officers on 44th Avenue just west of Sheridan Boulevard,” Officer Kirk Firko, of the Mountain View Police Department, said of the driver of a white Dodge Durango believed to have instigated the wreck.

Firko said the officer estimated the Dodge was traveling about 100 mph.

“The officer was going to make an attempt to try and stop him, but due to the capabilities of (the officer’s) vehicle, after about four blocks, he lost sight of the suspect,” Firko said.

Melissa Taylor, a spokeswoman for the Denver Fire Department, said one of the injured was taken to a hospital with second- and third-degree burns.

Denver police said the driver of the Jeep died Monday.

Denver police did not provide an update on the condition of the two injured.

Raquel Lopez, a Denver police spokeswoman, said the man arrested was taken to a hospital with injuries that are not believed to be life-threatening.

Ron Beall, a witness, said he heard the wreck and a loud explosion.

“I saw maybe a three-story (column of flames from) a gas tank blowing up,” Beall said.

Beall said he saw a passenger in the Jeep engulfed in flames rolling around on the ground. He said the Jeep’s driver was stuck inside.

Paramedics pulled the driver out and were using extinguishers to knock down the blaze, Beall said.

Elijah Roseboom said he saw a white Dodge Durango involved in the crash speeding east on 44th Avenue near Lowell Boulevard.

Roseboom said the Durango was moving in and out of traffic and running red lights in the moments before the wreck.

“He was going really fast, I know that,” Roseboom said. “His tires were even spinning out from how fast he was going.”