The U.S. Attorney's Office for New Jersey says 31-year-old John Musbach, of Haddonfield, entered the plea in federal court on Thursday.
Investigators said in 2015, Musbach was exchanging pornographic videos and pictures with the victim, who was 13 years old at the time.
According to court documents, the victim's parents were the ones who found the messages exchanged with Musbach on the online chat room, and they notified authorities.
In May of 2016, authorities say Musbach repeatedly communicated with the administrator of a purported 'murder-for-hire' website, intending to have the teenager killed so the victim could not testify in court.
Musbach asked if a 14-year-old was too young of a target, and was told that would not be a problem. He is then accused of paying 40 bitcoin (worth $20,000 at the time) for the hit.
When Musbach asked when the killing would happen, he was pressed for another $5,000. When he tried to cancel and get a refund, the administrator revealed the website was a scam and threatened to go to law enforcement.
U.S. Attorney Philip Sellinger says Musbach faces up to 10 years in prison and hefty fines.
The video in the player above is from our original report.