YAKIMA, Wash. — Investigators believe Preston Yahne, 22, a 2009 Prosser High School graduate known by his family for his upbeat text messages and effortless conversation, was killed, stuffed into his trunk and burned over a drug argument.

Two Grandview suspects in Yahne’s slaying made preliminary appearances in separate courts Wednesday.

Though they have not been charged, Robert McCorkindale, 24, is in the Benton County jail in Kennewick with a $250,000 bond, and Laura Bancroft, 19, is in Yakima County jail for their alleged roles in Yahne’s death. Bancroft’s bond is $500,000.

Yahne’s family remembers him as a talkative, sometimes flirtatious, young man who made friends easily.

“He could become your best friend in, like, five minutes,” said Kortney Yahne, his twin sister. “He was just that friendly.”

The family knew little about the alleged drug connection except what the investigators told them and said they don’t recall him ever mentioning either suspects’ names before.

Arrest affidavits from both counties say that McCorkindale told investigators he stabbed and ran over Yahne more than once following a drug dispute on June 14, stuffed him in the trunk of his own car and burned the vehicle the next day.

Yahne’s family reported him missing June 16 and a tow truck operator found the charred body, mostly just bones, on June 18. Medical examiners established his identity late Tuesday afternoon and still have not announced an official cause of death.

The vehicle and body were found near Emerald and South Emerald roads in a remote location south of Sunnyside, though detectives suspect the killing actually happened in Benton County, said Lt. Chuck Jones of the Benton County Sheriff’s office.

He would not disclose where.

McCorkindale told detectives that he met Yahne in a “remote location” for a drug deal on June 14 and Yahne pulled a knife during an argument, according to an affidavit filed in Benton County Superior Court by Benton County Sheriff’s Deputy Scott Runge.

McCorkindale said he then took the knife, stabbed Yahne with it, ran over him twice with the victim’s 2008 Dodge Avenger until he was dead and put the body in the trunk, the affidavit said.

The next day, McCorkindale told investigators, he drove Yahne’s car to Emerald Road and burned the vehicle, the affidavit said.

Yakima County court documents tell a similar story, but added that McCorkindale told investigators he ran over Yahne more than once just to make sure he was dead.

Bancroft was with McCorkindale during the killing and disposal, according to a probable cause affidavit filed in Yakima County Superior Court by Yakima County Sheriff’s Sgt. Mike Russell.

Witnesses told investigators they saw the couple around noon on June 15 leaving the scene of the burning vehicle on foot toward Sunnyside, Russell’s affidavit said.

Phone records showed Yahne’s cellphone had been used to call a house the couple was living in three times on June 15, the affidavit said. The owner of the home, Bancroft’s grandfather, told investigators the couple arrived in the Avenger, which they said Yahne had loaned them, according to the affidavit.

When deputies found McCorkindale, the suspect directed them to the place where he said the altercation occurred, the affidavit said.

McCorkindale and Bancroft both attended Prosser High School for at least one year but then left the district, said Principal Kevin Lusk.

Both have criminal histories.

McCorkindale has two felony drug convictions in Yakima County, as well an attempt to distribute in Salt Lake City. In April, he was convicted of unlawful possession of a firearm after he was caught prowling a vacant property on Chambers Road southeast of Toppenish.

Bancroft has been convicted in Benton County juvenile court of threatening the mother of a girl she was accused of beating up and shoplifting candy from a Prosser grocery store, and for violating a no-contact order for calling her mother-in-law in Benton County. In 2011 in Yakima County, she was charged with assaulting her then-husband Jarod Bancroft, but the case was dismissed.

Besides his twin sister, Yahne was close to his family — his stepfather Joe Villanueva, mother Angie Villanueva and older stepsister Sharrae Villanueva — they said.

He texted short encouragements to them every day and cracked jokes often.

At Prosser High, Yahne played football and baseball and showed pigs and goats at fairs through the school’s FFA club. He also was his senior class’s vice president.

After he graduated, he followed Sharrae into the Air Force, serving two years as an airman first class security officer at Minot Air Force Base in North Dakota.

He asked for a discharge and returned home in January 2011, where he lived with his folks northwest of town, attended some classes at Columbia Basin College in Pasco and worked at a local bakery frosting cakes and cookies.

He spent his down time shooting baskets at E.J. Miller Park, playing video games and drawing in his sketchbook. He had recently been working on a butterfly tattoo design for his mother.

Tattoos ran in the family. He and Kortney both had tattoos of each other’s initials, his hidden in a tulip on her ankle, hers adorned with a tribal band around his arm.

His family last saw him June 13, the day of Kortney’s graduation from the Yakima Valley Community College, where he had expressed interest in attending to study chemical dependency counseling.

He called them the next day — the night investigators believe he was killed — to make sure he knew the time of a celebratory barbecue in Kortney’s honor scheduled for June 15.

He never showed.

“He’s late,” Angie Villanueva remembers saying. “That’s just not Preston.”

• Ross Courtney can be reached at 509-930-8798 or rcourtney@yakimaherald.com.