A bicyclist was killed Wednesday morning in a collision with an 18-wheeler truck in Porter Square, Cambridge Police said.

The accident occurred around 8:00 a.m. on Massachusetts Avenue, opposite of the Porter Square Shopping Center, according to police spokesman Jeremy Warnick. 

An eyewitness who chose not to be identified said that she heard a strange engine noise and then a "screech" right before the incident.

"Then I saw pieces flying in the air," she said. "I don't know if it was body parts, backpack, helmet. There were pieces of something flying in the air."

The truck driver did remain on the scene. There was no report of charges being filed.

The identity of the cyclist, a male, will likely be released by the district attorney's office after a family member is notified, police said.

This is the second vehicle/bike crash in Cambridge this week. Police reported that a cyclist was transferred to a local hospital on Monday following an incident near Broadway and Portland Street. The bicyclist's injuries weren't life-threatening, police said.