KNOXVILLE, Tenn. (WATE) – Two men who pleaded guilty of taking two homeless men from Knoxville to the Great Smoky Mountains National Park to be raped have now learned their sentences.

Dusty Oliver, 41, and Richard Graham, 49, pleaded guilty to two counts of aggravated sexual abuse. Oliver was sentenced to 300 months in prison while Graham was sentenced to 230 months.

Both sentences will be followed by a 15-year period of supervised release and both men will have to register as sex offenders.

In June 2012 and again in November 2015, the pair raped two different male victims in the Great Smoky Mountains National Park after picking them up in Knoxville.

A Justice Department release said the two men, “preyed on homeless, drug-addicted, heterosexual males, who they believed were unlikely to report their attacks to law enforcement.”

One of the victims 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 the victim.

The victim was able to photograph Graham, who was sitting in the passenger seat of the vehicle. The photo was distributed by the Blount County Sheriff’s Office and led to the identification of Graham and Oliver.

“I want to express my thanks to ISB investigators, park rangers, and the Blount County Sheriff’s Office for their perseverance and hard work that led to the conviction and sentencing of these two men responsible for heinous crimes within the park,” said Great Smoky Mountains National Park Superintendent Cassius Cash. “To ensure that we’ve heard the voices of all victims, investigators continue to welcome any information about additional assaults that may be associated with Graham and Oliver.”