PORTLAND – A Boston man was sentenced Wednesday in U.S. District Court to nine years and seven months in prison for stalking his ex-girlfriend in Kennebunk before breaking into her apartment and assaulting her.

Andre Winston, 26, pleaded guilty March 23 to the federal charge of interstate stalking.

Winston made numerous telephone threats to harm the victim before he traveled to Maine, where he attacked her on May 11, 2005, according to court records. She suffered lacerations on her arm and back from a sharp-edged weapon, leaving her permanently disfigured.

The investigation that led to Winston’s conviction was conducted by Kennebunk police and the state Attorney General’s Office, according to U.S. Attorney Paula Silsby, who said the prosecution reflects how federal laws can be used to fight domestic violence crime in Maine.

State officials elected to drop their prosecution of Winston after Silsby’s office decided to pursue the case, said Kennebunk Detective Sgt. Bob McKenzie.

“We were very happy to hear the sentence,” he said.