Colorado prison officials said an inmate assaulted Aurora theater shooter James Holmes and a prison officer at the Colorado State Penitentiary.
Mark “Slim” Daniels, 27, will be charged with assault on a correctional officer and assault on Holmes, 27, Adrienne Jacobson, a spokeswoman for the Colorado Department of Corrections, told the Denver Post.
Daniels reportedly lunged at Holmes, taking several swings at him, the Associated Press reported. Holmes was not injured in the incident, which took place while the inmates were passing one another in the hall.
Holmes is allowed to spend four hours in day hall, and no inmates are allowed in his cell block.
The Denver Post was notified of the assault Friday through a letter whose writer claimed to be Daniels. The sender alleged the assault took place October 8.
Holmes was sentenced to life in prison without the possibility of parole in August for shooting and killing 12 people and injuring 70 others at a movie theater in Aurora, Colorado, in July 2012.