Jamie Satterfield

USA TODAY NETWORK - Tennessee

Authorities say a sex offender accused of using Facebook to lure innocent victims thought he was being invited to a 13-year-old girl’s house in Knox County for secret sex. He found her father – and her father’s gun – instead, federal court records allege.

Justin Kyle Phelps, 26, has been charged in a federal complaint accusing him of using Facebook to entice a minor to engage in sex. Assistant U.S. Attorney Matthew Morris is already seeking a psychological evaluation of the Monroe County sex offender, writing only that he has “reasonable cause to believe” Phelps might not be competent to stand trial, according to a motion filed this week in U.S. Disrict Court.

Phelps was initially jailed on state charges including solicitation of a minor related to the same incident. Few details were released. Those charges are still pending. He was charged federally Friday under a separate federal law.

Phelps is accused in the federal case of posing as two different teenagers on Facebook and using those identities to convince the 13-year-old victim he was a teenager and to disclose her address.

Phelps allegedly was climbing into the girl’s bedroom through an open window when the girl’s mother first realized something was wrong and spooked him off in March. When he showed up a second at the same window hours later – this time through the girl’s parents' own trickery on Facebook – her father was waiting with a gun, according to a complaint filed by Knoxville Internet Crimes Against Children Task Force Agent Chris L. Jones.

Phelps ran but a later probe would lead to his arrest days later, again through Facebook.

Jones outlined the events in the complaint.

In December, he wrote, the girl received a “friend request” from someone pretending to be a 13-year-old girl named “Vicky.” The pair began messaging, initially talking about a shared interest in modeling.

The talk soon turned darker, with “Vicky” pushing talk of oral sex and offering to introduce the girl to a teenage boy who could “teach her” about it, Jones wrote.

“The victim stated that she then received a friend request from ‘Justin Meh’ who claimed to be 17-years-old,” Jones wrote.

Over the next two months, “Vicky” and “Justin” – both of whom authorities contend was Phelps – continued talk about oral sex, tried to coax the girl to send nude photos and eventually convinced her to disclose her address.

On Feb. 12, “Justin” told the girl via Facebook he was on his way to her home, saying he “lived in another county which was about an hour’s drive from Knoxville,” Jones wrote. Phelps was living in Monroe County at the time, the complaint stated.

At some point, the girl’s mother “heard the family dog barking” and immediately went to check on her daughter, Jones wrote. Just as the mother entered the bedroom, she saw a “very thin male” trying to climb through an open window. He ran at the sight of her.

The Knox County Sheriff’s Office searched the area but found no one. Deputies left. It was then, Jones wrote, that the girl confessed of her conversations on Facebook.

Her parents decided to take matters in their own hands, messaging their daughter’s new friends “Vicky and Justin” while pretending to be their daughter. They invited “Justin” back to the house.

When “Justin” showed up, again trying to climb through the girl’s bedroom window, her father was standing there with a gun.

“The victim’s mother stated that the offender fled the scene again and did not return,” Jones wrote.

This time, the ICAC unit was summoned, and Jones and supervisor Tom Evans got to work tracking the Facebook accounts to Phelps and discovered he already had been convicted in September 2011 of trying to sexually exploit another minor and was on the state’s Sex Offender Registry after wrapping up his punishment in September 2015.

Jones created a fake Facebook account to lure Phelps back to Knoxville with a promise he’d be having oral sex with a 13-year-old girl. When he showed up at the previously-arranged meeting place, Jones arrested him, according to the complaint. Neither that location nor the victim’s address is listed in the complaint.

Jones wrote in the complaint a search of Phelps' phone revealed evidence of other potential victims. He did not elaborate on whether more charges could be coming Phelps' way.

Follow Jamie Satterfield on Twitter: @jamiescoop