WARRENVILLE, Ill. (CBS) — A motorcyclist was killed in a crash on the Ronald Reagan Memorial Tollway over the weekend, but there are differing stories being told about what caused the accident.

As WBBM Newsradio’s Bernie Tafoya reports, Illinois State Police say they are still investigating the crash that killed Nicholas Linton, 29, of Aurora, this past Friday night. But they say Linton was killed when he swerved to avoid running into another motorcycle on I-88 near the Winfield Road exit.

LISTEN: WBBM Newsradio’s Bernie Tafoya reports

But Linton’s motorcycling buddies tell a different story. They say a State Police squad car cut off the motorcycles in traffic, and that Linton was thrown from his bike when he swerved to avoid the police car.

“Basically, they got cut off by the police,” said Oscar Flores, who was riding his own bike about 150 feet behind Linton and the third motorcyclist. “They slammed on the brakes right in front of my two friends.”

After being thrown from his motorcycle, Linton’s friends believe he was hit by a passing truck. The third motorcyclist was able to pull off to the shoulder of the road.

Friends also said that the State Police patrol car did not have its lights or siren on as it approached Linton and his fellow motorcyclists on I-88.

Flores said he did not know the car was a State Police vehicle until he passed.

“He came up from behind,” Flores said. “I didn’t know it was a cop or anything. I moved over to let the car pass and that’s when I noticed it was a police car.”

According to State Police, the accident is under investigation, and no more information could be released until at least Tuesday. State Police said it was still unknown whether drugs or alcohol played a role in the accident.

Linton’s friends said he had not been drinking and that he was wearing a helmet at the time of the crash.

Family, friends, and club members have since approached the Chicago Far South Side branch of the NAACP for help in pursuing a full investigation of what happened Friday night.

“A friend of Nick called us and asked us if we would get involved with the accident. The way it happened it was the state trooper’s fault,” said David L. Lowery Jr., president of the NAACP chapter. “It is so tragic what happened it is unbelievable.

“It’s unusual that a state trooper would get in front of a bike to stop it, rather than behind it,” Lowery continued. “The NAACP wants to make sure that justice is done, that it was truly an accident and not something a state trooper caused out of protocol.”

The Aurora Beacon-News contributed to this report, via the Sun-Times Media Wire.