(CNN) A British man who is already in US federal custody will face a second-degree murder charge in connection with the disappearance of his wife, who went missing while the couple sailed through the Florida Straits last year, according to a criminal complaint. Isabella Hellman was reported missing nine months ago after the Coast Guard received a distress call from her husband, Lewis Bennett. Bennett, 41, was rescued from a life raft about 30 miles west of Cay Sal, Bahamas, an island near Cuba's northern shore. An FBI agent says in an affidavit filed Saturday that he believes Bennett intentionally scuttled the couple's vessel late on May 14 or early May 15. According to court documents, Bennett was sentenced Tuesday to seven months in federal prison for transporting stolen gold and silver coins.