Charles Manson, a mass murderer serving nine life sentences, has returned to Corcoran State Prison in California after a brief hospital stay.
Manson, 82, was hospitalized Tuesday for an undisclosed medical issue.
Officials with the Department of Corrections and Rehabilitation (CDCR) declined the L.A. Times' request for comment, saying Manson's medical information is private.
TMZ originally broke the news.
The cult leader conspired to murder seven people in 1969, with movie star Sharon Tate and coffee heiress Abigail Folger among his victims.
Prison officials told the L.A. Times that Manson had violated "hundreds" of rules while in prison, including having a cell phone and being in possession of a homemade weapon.
The convicted murderer has been denied parole 12 times and his next parole hearing isn't until 2027.
The Associated Press contributed to this report.