Lawyers for former crime boss James "Whitey" Bulger say they'll file their appeal of his 2013 convictions with the 1st U.S. Circuit Court of Appeals on Aug. 14.
Eighty-four-year-old Bulger is serving life in prison. He was convicted in a broad racketeering case, including 11 killings and other gangland crimes in the 1970s and 80s.
The notice Thursday didn't give details. Bulger's lawyers have said he believes he should have been allowed to argue that a now-deceased federal prosecutor gave him immunity.
Bulger headed Boston's Irish mob and was an FBI informant against the rival New England Mafia. His case became a major embarrassment for the FBI when it was learned corrupt Boston agents took bribes from him and protected him.
He was a fugitive for 16 years until his 2011 arrest in California.