A Plymouth police officer injured in a motorcycle collision Tuesday afternoon died several hours later at Massachusetts General Hospital, Police Chief Michael E. Botieri said at a press conference.

The officer, 43-year-old Gregg Maloney, who was married and the father of two teenage boys, was a 17-year veteran of the Plymouth Police Department and a member of the motorcycle unit since 2009, Botieri said.

“The next several days and weeks will be difficult for this department,” he said.

The cause of the crash that killed Maloney is under investigation, Botieri said. No other vehicles appeared to be involved, although another motorcycle officer was riding alongside Maloney at the time of the accident on Samoset Street. Maloney was taken by MedFlight to a hospital after the crash.

“There’s nothing evident at the scene telling us what happened,” Botieri said. “There was no obvious reason for the bike to go down.”

The chief characterized Maloney as “well-liked” and an active member of the law enforcement community.

“Incidents like this show just how dangerous these jobs can be on a day-to-day basis,” James Machado, executive director of the Massachusetts Police Association, said. “These guys are heroes.”

Todd Feathers can be reached at todd.feathers@globe.com.