Police announced the arrest this morning. Martel was found stabbed to death yesterday in the couple's shared Waltham, Mass., apartment. The district attorney said Remy had been detained earlier this week after a domestic dispute with Martel, but was released without charges.
Remy was arrested and charged with assault and battery in 2005 after being accused of beating up his girlfriend. In 2009, Remy was fired from his job with the Red Sox after being implicated as a steroids dealer, after which he admitted to using steroids himself.
An MLB investigation did not find evidence he had ever sold them to players.