DENVER -- One of the four bikers who were mowed down by a black Lexus on Tuesday afternoon remains in critical condition.

Mike McGinley Sr., Mike McGinley Jr., Johnnie Baker and Byron Waggner were riding their Harley Davidsons on Speer Boulevard near 8th Avenue when a car entered the intersection and crashed into them.

McGinley Sr., 45, was thrown about 20 feet and knocked unconscious, friends said. He was immediately taken into surgery, suffering from several internal injuries, including a ruptured spleen. He remains in critical condition at Denver Health Medical Center.

His 18-year-old son is in fair condition and Baker is in serious condition with possibly a fractured hip, police said. Waggner, 46, was treated and released.

None of the bikers was wearing a helmet but, fortunately, none of them had serious head injuries, police said.

The crash occurred before 3 p.m. just outside Denver Health. Police said the driver of the black Lexus was trying to make a turn when she crashed into all of them.

The Lexus driver was treated for minor injuries and released. She may face charges of careless driving, pending the conclusion of the police investigation.

Jeff Thomas said he was riding with the group when he got caught behind at a red light. Just as he was about to catch up to his friends, he saw the crash occur in front of him.

"I thank God that they're all alive. From what I've seen of that, I don't know if I'll ever ride again ... It was pretty nasty. It really was," said Thomas.

Thomas said that the motorcycle riders had the green light.

"The intersection was clear, they came through 8th Avenue and this black car here in the intersection just came out of nowhere, by itself, and ran right in front of the bikes and they all collided with the car," Thomas said.

The crash tied up traffic in that busy downtown area for three hours.