GATLINBURG, Tenn. (WATE) – Two men could face life in federal prison after pleading guilty into taking two homeless men from Knoxville to Great Smoky Mountains National Park to be raped.

Dusty William Oliver and Richard L. Graham agreed to plead guilty on Thursday to aiding and abetting aggravated sexual assault of two men. They could be sentenced to life in prison.

According to documents filed in U.S. District Court in Knoxville, a homeless man, referred to as RP, was walking along Chapman Highway while intoxicated in June 2012 when Oliver and Graham approached in a vehicle asking if he wanted a ride to the Bristol, Tenn. for the races.

RP realized once inside the vehicle that it was headed the opposite way from Bristol and the three soon arrived at a trailhead of the Appalachian Trail.

The three began hiking and Oliver and Graham soon overpowered the RP and raped him, according to court filings.

RP feared the two would kill him and leave him on the trail but was later dropped off by the two at a nearby gas station, according to the court documents. A rape kit was conducted at UT Medical Center.

In November 2015, another homeless man, called CN, accepted a ride from Oliver and Graham after meeting the two while walking on Chapman Highway toward Seymour, the court documents said. They stopped at Look Rock Trail and hiked to Lookout Tower where CN was raped by the two.

After the assault, Graham and Oliver dropped CN at the intersection of Alcoa Highway and Kingston Pike in Knoxville. He then walked to UT Medical Center where a rape kit was performed.

CN told investigators that they stopped at two gas stations that night. Surveillance footage from the two gas stations showed a man with tattoos on his left arm and a Jeff Dunham T-shirt which matched the description given by CN.

CN was able to photograph Graham, who was riding in the passenger seat of the car, with his phone. The photos were distributed by the Blount County Sheriff’s Office which led to the identification of Graham and Oliver.

After interviewing the two suspects, both Graham and Oliver voluntarily provided DNA swabs for analysis. In October of 2018, results showed Graham’s DNA was a 100 percent match of the DNA found in the 2012 rape kit of RP. In May of 2019, the DNA comparison showed a moderate support ratio of DNA found in the rape kit of CN matched that of Graham.

While the plea agreements were submitted on Thursday, the case has yet to be heard by a judge for plea acceptance and sentencing.