A New Bedford man was convicted of fatally beating another man with a hammer during a robbery, stealing the victim’s car, and fleeing to Connecticut. Thomas Gardner was convicted in Superior Court Tuesday of first-degree murder in the November 2011 death of Michael Duarte. Gardner was sentenced Wednesday to life in prison without parole, the mandatory sentence for first-degree murder. The men met at a New Bedford home Duarte was interested in buying, prosecutors said. The house was owned by Gardner’s former wife, and he was staying there in violation of a restraining order. Prosecutors said Gardner beat Duarte with a hammer and stole money, a cellphone, and his car.