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EL PASO COUNTY, COLO. -- El Paso County sheriff's deputies have released more disturbing details in the case of a 20-year-old man arrested for allegedly sexually assaulting three children.

Brandon Rankin, a Colorado Springs resident, allegedly sexually assaulted three children while babysitting them. Rankin's sister-in-law told a friend about the incidents, and the friend reported it to deputies.

According to the arrest affidavit, one of the victims told deputies she felt uncomfortable because Rankin would sit close to her on the couch. She also said Rankin would try to hug her before she went to bed, and she felt she would have to because she was afraid of him. She also said Rankin would play "tickle games" with her and touch her inappropriately.

Another victim told deputies in December Rankin engaged in sexual acts with them even though they did not want to, then told them not to say anything. Another victim, a 6-year-old boy, said he saw the act and called it "disgusting."

The affidavit states Rankin took naked pictures of the young girls on his phone while they were sleeping, and the girls tried to stay up as late as possible because they did not trust him. Once the girls were asleep, Rankin wrote on them with lipstick and took pictures on his phone.

Another victim, a 6-year-old girl, told deputies Rankin had engaged in sexual acts with her against her will, made her watch sex scenes in movies and took naked pictures of her on a bed.

Deputies said some of Rankin's alleged victims now live in El Paso, Texas. According to the friend who originally reported the incident, Rankin faced similar allegations while living in New York, but police dropped charges when they believed some victims had been lying.

Rankin faces three counts of sexual assault on a child and three counts of sexual assault on a child by one in a position of trust.

Rankin's mother is a member of the military, and according to the friend, tried to cover up the situation by telling others who knew about the allegations not to go to police.