Colorado theater shooter James Holmes was briefly attacked by another inmate, but uninjured, at the Colorado State Penitentiary, PEOPLE has confirmed.
It was a “brief incident in passing in a hallway” between the convicted gunman and Mark Daniels, state Department of Corrections spokesperson Adrienne Jacobson tells PEOPLE.
A guard was also involved, as inmates are escorted at all times, Jacobson says.
Jacobson says the incident was “very, very minor” and that Daniels would face internal disciplinary measures, not additional criminal charges.
The attack occurred on Oct. 8, according to a letter obtained by the Denver Post which claimed to be from Daniels.
Jacobson was unable to confirm the date of the attack.
The DOC has not considered moving the gunman from the penitentiary, where he is serving a life sentence, Jacobson says.
Holmes was sentenced in August to life in prison without the possibility of parole, after opening fire in a crowded theater in 2012, during a midnight showing of The Dark Knight Rises.
He killed 12 and injured 70, and was convicted in July on 24 counts of first-degree murder.
Daniels is serving time for menacing, auto theft, assault and smuggling contraband into prison, according to the Post.
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