When a man looks like he is doing something suspicious outside a neighbor's home and he starts running away when you confront him, what do you do?

David Richichi and Kyle Doman didn't hesitate when they found themselves in that situation on Halloween. They chased him.

Richichi and Doman split up and cornered the man a block away. Then, they tackled him.

"When he wouldn't answer our questions, we just had a little tussle and proceeded to detain him while Kyle called police for us," Richichi told CBS4.

Wesley Cox allegedly was that man, and he initially tried to deny to Richichi and Doman that he was up to something.

Cox soon admitted, though, that he had been trying to make a video of their neighbor as she undressed. He tried to erase the videotape.

"They were also able to keep him from (erasing) the video tape, which gave us a great deal of helpful information," Police spokeswoman Sarah Huntley said.

After police came and arrested Cox they pieced together a long -- and creepy -- set of crimes they think Cox is guilty of.

Cox, 44, tentatively faces charges of misdemeanor trespassing, unlawful sexual contact and invasion of privacy, and more charges are possible.

Huntley said Cox was released on bond from the Boulder County Jail but was arrested again Nov. 15 after police obtained a search warrant.

Police said Cox's camera had nude images of several women on it and a search of Cox's home yielded scores of women's underwear and garments allegedly stolen by Cox. They included a Boulder High School cheerleader's uniform, a bikini and dirty socks.

Officers collected many videotapes Cox allegedly made, all within the past 6 months. They apparently were of people having sex or while they were naked.

Investigators say Cox targeted women living within a 2-mile radius of his home. A police statement said it appeared he "broke into women's homes, stole their belongings and then became obsessed with the victims."

Cox is due in court next Tuesday.