CRANBERRY TWP — A convicted child pornographer was arrested Tuesday after he showed up for what he thought would be sex with a 5-year-old girl, authorities said.

The girl and her “mother,” with whom he had been communicating online and by text message, were actually undercover agents from the state attorney general's office.

The agents arrested David P. Ellenberger, 43, of Summit Township at a predetermined place in Cranberry Township.

Ellenberger was arraigned Wednesday on felony charges of unlawful contact with a minor, attempted rape of a child, attempted deviate sexual intercourse with a child and criminal use of a communication facility.

He also is charged with attempted indecent assault, a misdemeanor.

Ellenberger, who is a registered sex offender, is in the Butler County Prison on $50,000 bail.

The attorney general's office Tuesday was investigating online advertisements soliciting sex from children when agents came upon Ellenberger's ad.

Agents, posing as the 5-year-old's mother, responded to it and in turn, Ellenberger texted back that he was interested in having sex with the girl, according to court documents.

Ellenberger and the purported mother exchanged texts, documents said, and they agreed to meet in Cranberry.

At 2 p.m., authorities waiting near the pre-arranged meeting spot saw Ellenberger in his pickup truck. They arrested him.

During an interview with investigators, he admitted the online solicitation and “indicated that he knew the child that he was supposed to meet and engage in unlawful sexual activity was only 5 years old,” the charging documents said.

Ellenberger was on probation from his 2006 Butler County Court conviction for possessing and disseminating child pornography.