A former volunteer photographer for WXPN's award-winning Kids Corner show had cocaine and two Hello Kitty girls' socks in his pockets when federal agents arrested him Friday on child pornography charges.

Only months after he made bail in a state case involving similar crimes, prosecutors say, Mark Wilkens had filled his cellphone and laptop with dozens of new sexually explicit photos of children.

That allegation was detailed Tuesday in court filings that prompted a federal magistrate judge to order Wilkens, 57, detained until trial.

"Wilkens continues to involve himself in the sexual exploitation of children, regardless of the directives of the court, and in flagrant disregard of the laws protecting our children," Assistant U.S. Attorney Michelle Rotella wrote.

Calling Wilkens a danger to the community, she also cited the proximity of three day-care centers to his Lawncrest apartment and an unregistered .357 caliber handgun FBI agents found during a search on Friday.

His lawyers - William Davis Jr. and John J. Flannery Jr. - did not oppose prosecutors' push to keep their client behind bars.

Wilkens is accused of taking explicit pictures of girls between the ages of 3 and 10 while shooting photos for WXPN-sponsored children's events at the Franklin Institute, Morris Arboretum, and the Camden Children's Garden between August 2010 and July 4 of this year.

During his nearly three decades volunteering with the station, he captured dozens of images of girls changing into bathing suits or while parents changed their diapers at the events, prosecutors said.

Wilkens was caught in July while trying to use a self-serve photo-developing kiosk at a Wal-Mart store. According to court filings this week, the machine malfunctioned, sending the images he uploaded to the store's help-desk clerks, who later called Philadelphia police.

Confronted by investigators, Wilkens admitted his crimes almost immediately, the filings say. Unmarried and childless, he told police he was lonely and was sexually attracted to prepubescent girls, prosecutors said.

He was arrested on state child exploitation charges, entered a not-guilty plea, and was released a few days later on a $5,000 bond.

Federal authorities adopted the case after reviewing the evidence and filed the new charges against Wilkens that were unsealed last week.

If convicted, he faces a mandatory minimum sentence of 15 years in prison.