Brookline police are searching for a man who stole a car and fled to an MBTA station after trying to rob a Star Market on Beacon Street Wednesday, a spokesman said. After leaving the market, the suspect ran onto Beacon Street and commandeered a Lexus sport utility vehicle that was stopped in traffic, the spokesman said. The driver jumped out and escaped unharmed. The suspect fled to Brookline Hills Station on Tappan Street, where he left SUV. The suspect is described as a heavy-set white man in his 50s with gray hair and a scruffy beard. He is approximately 6 feet tall, police said. The police spokesman said no one was injured in the incident, and MBTA Transit Police provided a dog to assist in the search.