MIT Police helped return a dog and owner after the theft of a car in Brookline. (Photo: MIT Police via Facebook)

A teen from Cambridge was taken into custody by police Wednesday after a five-day investigation involving a BMW stolen out of Brookline with a dog inside.

The search began Saturday after a woman shopping at a T.J. Maxx on Harvard Street in Brookline realized at about 4:15 p.m. that her 2017 BMW had been stolen – and the dog that had been waiting in it.

“The vehicle was unlocked and is push-to-start, and the owner left the key in the console,” said Jeremy Warnick, director of communications and media relations for Cambridge police.

An alert went out at around 4:30 p.m. for the stolen car, and just around 15 minutes later Cambridge police got a call that it may have been spotted at Amherst and Wadsworth streets in MIT/Area II, where the driver got out of the car, pushed the dog out, climbed in again and “backed up in the car, nearly injuring three students, and drove off toward Memorial Drive,” Warnick said.

The dog was picked up by students and MIT and Cambridge officers, after which Cambridge police saw the stolen BMW parked and empty on Winter Street. “The owner was reunited with the dog and vehicle later that night,” Warnick said.

A description given for the suspect matched that of a Cambridge teen who was arrested last week as a suspect in a February carjacking in Medford. He was found early Wednesday in Cambridge by Cambridge police detectives and taken into custody for warrants from Norfolk Juvenile Court on charges of larceny of a motor vehicle and larceny over $1,200 and Middlesex Juvenile Court on charges of receiving a stolen car, receiving stolen property and a plate violation.

More charges from Cambridge police are expected, Warnick said.