(CNN) Notorious mobster James "Whitey" Bulger died only one day after being transferred to US Penitentiary Hazelton in October 2018.

Almost one year later, his family has filed a wrongful death claim against the US Department of Justice, US Bureau of Prisons and US Marshals Service, alleging a conspiracy among them to deliberately harm him.

"To be clear, we do not believe that the transfer to FCI Hazelton and placement in the general population was simply dangerous, negligent, reckless, and irresponsible; we believe it was also intentional and part of a conspiracy among BOP, DOJ employees, and others to intentionally cause Mr. Bulger's serious injuries and death," Bulger family attorneys Hank Brennan and David Shoen wrote in their letter notifying the Department of Justice of their wrongful death claim.

Representatives for the Department of Justice, the Bureau of Prisons and the Marshals Service declined to comment Monday. A representative for the Bureau of Prisons added that the US Attorney's Office and the FBI are investigating Bulger's death as a homicide and that they would not be releasing further details to protect the integrity of the investigation.

The Bulger family is seeking $200 million for damages and injuries, though the family said in a statement it has no expectation of monetary gain, as "any award to the estate will be subject to numerous claims, not the least of which are those lodged by the Department of Justice."

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