Arizona Inmate Crawls Past Guard, Reportedly Planned to Assault Female Inmate, on Video

A male inmate in an Arizona jail was caught crawling past a security guard to reach the facility's female side ... where, according to court documents, he said he intended to "rape" a female inmate.

The disturbing incident unfolded in front of surveillance cameras in April ... Justin Avery was seen sneaking past a guard at 4 AM at the Maricopa County intake facility, where he was being held for allegedly sexually assaulting 5 women near Arizona State University's Tempe campus.

According to court docs obtained by ABC15 , he snuck over "like a spider" after he said he was attracted to a female inmate's "fat a**."

The docs say Avery made it over to the women’s side, and dropped his pants behind a sleeping inmate ...  allegedly later admitting he planned to sexually assault her.

Apparently, he was stopped when another woman spotted him and screamed for him to get off her ... prompting a security officer to intervene.

According to the report, he subsequently 'fessed up to his actions and was slapped with an additional count of sexual assault.

He’s reportedly due in court next week.