Christopher Edward Terry, Kyle Austin Drattlo and Brianna Harding were picked up while in Drattlo’s grandparents’ car.

A man pleaded guilty to two counts of first-degree murder Tuesday in the brutal stabbing deaths of his grandparents in 2013.

Kyle Austin Drattlo, who was 20 at the time of the murders, took the plea before Pima County Superior Court Judge Scott Rash, said Krisanne LoGalbo, a spokeswoman for the court.

Drattlo is scheduled to be sentenced July 28. He faces natural life for both counts, and is not eligible for parole, LoGalbo said.

On July 23, 2013, Drattlo’s grandparents, Erskin Fulgham, 87, and Mary Louise Fulgham, 83, were found in their home with stab wounds. Erskin also had been beaten and stomped. Mary Louise was killed as she sat in the living room, and Erskin, who was in need of an oxygen tank, was killed in the kitchen.

The next morning Drattlo and two friends — Christopher Edward Terry and Brianna Harding — were picked up by a deputy while traveling in the Fulghams’ 2004 Buick through Nevada.

The deputy learned the car was reported stolen out of Tucson and was associated with a double homicide. Drattlo told the deputy that when he left his grandparents home that “he must have left the front door open and he hoped his grandparents were OK.” He also said that his grandparents gave him $150 and kissed him goodbye, according to police documents.

Drattlo also told detectives that he “made a Juggalo family” with Terry and Harding, who were also in their early 20s at the time of the slayings. Juggalos are fans of the band Insane Clown Posse.

In 2011, the FBI formally classified the Juggalos as a gang. Arizona is one of the top five states in the U.S. reporting the most Juggalo gang-related criminal activity, according to a 2011 gang threat assessment.

Terry and Harding were both sentenced to prison in 2015.

Contact reporter Carmen Duarte at cduarte@tucson.com or 573-4104. On Twitter: @cduartestar