The United States attorney for Minnesota and the federal Drug Enforcement Administration are joining the Carver County investigation into the death of Prince.
"The DEA and U.S. Attorney's Office are able to augment this local investigation with federal resources and expertise about prescription drug diversion," the U.S. Justice Department said in a statement Wednesday.
The department declined further comment citing the ongoing investigation.
Investigators are probing whether Prince died from an overdose and whether a doctor was prescribing him drugs in the weeks before he was found dead at his home in suburban Minneapolis, a law enforcement official has told The Associated Press.
On the day he died, Prince was expected to meet with a representative of a California drug addiction rehab facility who hoped to convince the music superstar to come to recovery, an attorney representing the facility's founder said Wednesday.