Why did violence erupt at Critical Mass ride in Seattle?

Seattle police said they were still looking Saturday for one member of a group of Critical Mass bicyclists who allegedly attacked and injured a driver during an altercation Friday evening on Capitol Hill.

Two other bicyclists have been jailed. But some riders in the event said the driver instigated the incident by driving angrily into several bikers.

Just after 7 p.m. Friday, the group of at least 100 bicyclists was moving en masse down East Aloha Street when a man and his girlfriend in a Subaru station wagon tried to pull out of a parking spot, said Seattle police spokesman Mark Jamieson.

For years, Critical Mass has held monthly public bike rides through Seattle to demonstrate for bicyclists' road rights. The riders commonly engage in what they call "corking," in which several bikers block cars while the mass of riders passes.

According to Jamieson, witnesses told officers that as the Critical Mass group moved down the street blocking traffic, some riders got in the way of the Subaru and prevented it from leaving. Some bikers sat on the car and were banging on it, he said.

"The driver was pretty fearful that he was about to be assaulted by the bicyclists," Jamieson said.

According to police, the man tried to back up but bumped into a cyclist. "This enraged the group," Jamieson said.

Several of the cyclists bashed up the Subaru, shattering the windshield and rear window, Jamieson said.

The driver, whose name and age were not released, tried to drive away but hit another bicyclist, Jamieson said. Still, he drove about a block, to Aloha and 15th Avenue East, before the Critical Mass riders cornered the car and started spitting on it and banging against it, Jamieson said.

One bicyclist punched the driver through his open window, and another used a knife to slash the Subaru's tires, Jamieson said.

The driver got out of his car, was hit in the back of the head and suffered a large gash, police said.

Eventually police arrived and the crowd dispersed. Witnesses identified two bikers who they said damaged the Subaru. The two men, in their early 20s, were booked into the King County Jail for investigation of malicious mischief, Jamieson said.

Police interviewed and got the identity of the man who is accused of hitting the driver, but they turned him loose before a witness identified him as the attacker, Jamieson said. Police were trying to find him Saturday.

The driver was taken to a hospital. His injuries were not life-threatening, Jamieson said, and his girlfriend wasn't hurt. The bicyclists didn't suffer any serious injuries, Jamieson said.

Jamieson said it was too early to say whether the incident might change the way the Seattle Police Department handles future Critical Mass rides, which are held the last Friday of each month.

No one representing Critical Mass could be reached Saturday to comment.

But in e-mails to The Seattle Times and on online forums for Seattle bicyclists, some riders who said they were in the Critical Mass ride characterized the Subaru driver as the aggressor. They said the driver was impatient about waiting for the huge group of riders and yelled that he was late for a reservation.

Ryan McElroy, 25, of Bellevue, was riding with the group and witnessed the incident. Later, he said that the driver was under no threat from the bicyclists when he drove into them.

"He snapped. He deliberately hit the gas," McElroy said. The driver accelerated into two cyclists, pushing one of them across the street and under the car, and then ran the left front tire of his car over the cyclist's leg, he said.

McElroy said there was shouting back and forth, but the cyclists did not attack the car until after it had hit the two. He said the driver appeared to be trying to flee until one of the cyclists slashed the car's tires.

McElroy said some accounts made it sound as though the cyclists attacked the car first, and the driver was trying to get away. "Not true," he said. "The window-pounding did happen, but not until the cyclists were run over."

Tom Braun, 36, of Seattle, said the Subaru ran over his right leg. His bicycle was damaged beyond repair, he said, and he ended up in the emergency room. He suffered no broken bones, and was released, but is being monitored for possible internal injuries.

Braun said he first saw the driver of the Subaru "screaming at cyclists to get out of the way."

Some cyclists were explaining that everyone was nearly past, but the driver yelled about being late for an appointment, and drove directly into the crowd of cyclists, he said.

The front right side of the car struck Braun and dragged him along with his bike as he hung onto the front of the car, he said.

Then the driver ran over his leg and bike, and sped down Aloha, he said.

Another cyclist, Jason Gruenwald of West Seattle, said he was participating in the ride with his son when the incident began.

"It was quite scary for us passers-by on just a bicycle to see a person threatening to use their car as a weapon," Gruenwald wrote in an e-mail.

"As the man didn't like the fact he may have to simply wait until the people on the bikes passed, he let his rage and discomfort escalate the situation by challenging the bikers with violence."

Seattle Times staff reporter Carol Ostrom contributed to this report.