Colorado Springs Mayor John Suthers’ son-in-law was in critical condition Tuesday after a stolen vehicle fleeing Denver police struck the Uber he was riding in, killing its driver.

Mark Karla, 45, was at Denver Health Medical Center with “serious brain injuries,” Suthers said, after a hit-and-run accident about 1 a.m. Sunday.

Karla had attended a Garth Brooks concert with friends Saturday night. He called his wife, Alison Suthers, about midnight to tell her he was taking an Uber home from a friend’s house.

When she didn’t hear from him later that night, she called him but got no reply.

A few hours later, the mayor said, police called his daughter to tell her a man driving a stolen vehicle had run a red light and hit her husband’s Uber.

The stolen Jeep was traveling westbound on Colfax Avenue about 70 mph and hit the Uber headed south on Colorado Boulevard, Suthers said.

The Uber driver died immediately, he was told. Denver police spokesman Kurt Barnes would only confirm that one person was found dead. The Denver Post reported that the stolen Jeep also hit another vehicle.

“It’s a day-to-day situation,” Suthers said. “It’s a real tragedy. Janet and I love our son-in-law.”

Karla, a dentist, and Alison, a prosecutor in the Denver District Attorney’s Office, have been married about five years, Suthers said.

“He is just a very, very caring guy,” said Suthers, who went with him to Calcutta in November to help with his work.

“I was fortunate to go with him and learn so much about what a great man he is.”

Alison and Karla have a daughter, Izzy, who will be 3 in August.

Denver police have not released the name of the driver they arrested but did confirm that he fled in the Jeep after the crash. Suthers said police told him the suspect has a record.

“It is a terrible, terrible tragedy, and our family really appreciates all the support that we’ve gotten,” he said.