A 25-year-old suspect ran down a bike messenger, "sped off" and stashed a car in the Boston Common garage, leaving behind his car rental agreement in the glove compartment, prosecutors said today at the arraignment in the fatal Back Bay hit-and-run.

Malone Mesfun Kidanemarium, 25, pleaded not guilty this morning in Boston Municipal Court to a charge of leaving the scene of an accident resulting in death. He was ordered held on $25,000 cash.

If convicted, the Bay State College graduate faces a mandatory minimum one year in jail – and possibly more than two years in state prison. He was ordered to return to court next month for a pretrial hearing.

Richard "Rick" Archer, 29, a professional bike messenger, was out for an early morning recreational ride with a friend on Commonwealth Avenue April 30 when he was hit while crossing the road. He died May 2 at Massachusetts General Hospital, where Kidanemariam's family and court papers state the suspect works in administration.

He was arrested by Boston police last night after turning himself in eight days after the fatal crash on the advice of his attorney Patrick Troy and after learning police had cooperating witnesses against him.

Assistant Suffolk District Attorney Benjamin Megrian said officers responding to a call for help at Commonwealth Avenue and Clarendon Street shortly after 3:15 a.m. on April 30 found an unconscious Archer bleeding from his nose, mouth and ears.

Megrian said Archer's cause of death was blunt-force head trauma.

The friend Archer was riding with told investigators Archer had left the bike lane and crossed the street to talk with him.

"Upon hearing an approaching vehicle, the witness stated to the victim that he ought to move back to the bike lane so as not to block the right lane," Megrian said. "Shortly after, the approaching vehicle struck the victim, sending the bike into a parked motor vehicle."

Megrian said Kidanemariam, who had at least two passengers in the silver 2016 Toyota Camry with New York plates he had rented from Enterprise, then "sped off" and drove the wrong way up Berkeley Street.

Megrian said Kidanemariam stashed the dented Camry in the Boston Common garage 15 minutes later. It was located two days later.

Both passengers told police they were asleep and were awoken by the collision. One claimed Kidanemariam "panicked and continued to drive around until he parked the car," Megrian said.

The other, he said, said the damage to the car was so bad that Kidanemariam "can't even see through the windshield."

Police executing a search warrant "found a rental agreement in the name of the defendant in that vehicle," Megrian said.

Kidanemariam has no criminal record, he said.

Troy told the court a more reasonable bail would be $5,000.

"My client is not a man of substantial means," Troy said, "and neither is his family … At the end of the day, this is an absolute tragedy that the commonwealth has alleged is a failure to act appropriately, post incident."

Afeworki Kidanemariam, the uncle who "raised him up," said, "He is a child. Everyone knows him. He's very nice. Everybody's shocked by what happened."

The uncle declined to discuss the case. "I don't know anything," he said. "He's a very nice kid. That's what I know."

After this morning's proceeding, dozens of family members and supporters from Roxbury's Ethiopian community held a prayer service outside the courthouse.