Christopher Reynolds thought he was talking to a woman looking to exchange money for sex with her 13-year-old daughter, Bucks County prosecutors said Thursday.

Reynolds was adamant about certain graphic details while negotiating the price for the encounter, and even offered a higher rate so the woman could buy her daughter an emergency contraceptive pill, according to the affidavit of probable cause for his arrest.

But in reality, Reynolds was speaking to an undercover detective who investigates human trafficking. And Reynolds, 35, was arrested late Wednesday after driving nearly an hour from New Jersey to a motel in Bensalem.

Reynolds, of Browns Mills, Burlington County, has been charged with criminal attempt to engage or perform a commercial sex act with a minor, criminal attempt to commit trafficking in individuals, and related crimes. He was held in lieu of $500,000 bail, and there was no indication that he had hired an attorney.

District Attorney Joe Khan said Reynolds’ arrest “sends an unmistakable message to those who look to prey on children in our communities.”

“This is the exact kind of proactive, aggressive enforcement the public can expect from our office’s revamped anti-trafficking operation,” he said. “We are going to use every tool and technology at our disposal, and we will continue to hunt down those who attempt to exploit vulnerable individuals.”

Investigators say the undercover detective first started communicating with Reynolds on Tuesday, after he responded to an ad on a website offering “taboo” with an underage girl, the affidavit said.

After negotiating the price and duration of the encounter, Reynolds agreed to meet the girl’s mother at motel on Lincoln Highway. He nearly called off the appointment when detectives declined to send nude images of the girl, but relented when they sent a digitally de-aged photo of a female detective.

Investigators arrested Reynolds as soon as he entered the motel, the affidavit said. He was carrying $300 and a bottle of Mountain Dew, items the undercover detective told him to bring to the meeting while posing as the girl’s mother.

Reynolds is scheduled to appear before a district judge for his preliminary hearing on July 16.