Authorities in Cambridge, Massachusetts, say a police officer has been cited, but not arrested, in a hit-and-run over the weekend.

Twenty-eight-year-old Ryan Callinan of Wilmington is accused of leaving the scene after hitting a bicyclist at the intersection of Broadway and Portland Street Sunday evening.

Police say the victim has since been released from a local hospital after Callinan rear-ended her.

"She was doing everything she was supposed to do," said Cambridge Police Deputy Superintendent Jack Albert. "She had lighting on the back of the bike, she had reflective clothing on and she had her arm out indicating a left-hand turn."

Callinan, a five year veteran of the department, has not been arrested, but placed on administrative leave, police said.

Albert gave two reasons why Callinan was not charged.

"There's no mitigating circumstances, as we know right now, that would elevate it to a felony charge," Albert said. "Unless we witnessed the event, the accident itself, we would not place that person under arrest."

The investigation into the hit-and-run is being conducted by Cambridge police, Middlesex D.A.'s office and state police.

Callinan's arraignment date has not been set.