FLORENCE, Ariz. » A missing Phoenix-area couple were killed and buried in the yard of a man who told investigators he was high on methamphetamine when he shot the husband and wife, authorities said Thursday.

The disclosure came after the bodies of Michael Careccia, 44, an airline pilot, and his wife, Tina, 42, an accountant, were discovered on the Maricopa property of suspect Jose Valenzuela.

Pinal County Sheriff Paul Babeu said Valenzuela had borrowed a backhoe from an unsuspecting acquaintance to hide the bodies.

"Instead what he did was he built, not a makeshift grave, but an actual 6-foot grave," Babeu said. "He put these victims in that grave and buried them."

The grave was not initially noticeable because debris had been piled on top of it, the sheriff said.

During the investigation, Valenzuela acknowledged to authorities that he had done meth before the killings, sheriff’s spokesman Mark Clark said.

Valenzuela, 38, has been charged with two counts of first-degree murder. He was being held on a $2 million cash bond.

Babeu said Valenzuela was found with a .22 caliber revolver believed to be the murder weapon and made statements to an investigator that led to the search of his property.

"Essentially he confessed," Babeu said at a news conference.

The couple was reported missing June 22 by Michael Careccia’s son after Tina Careccia didn’t show up at the construction company where she worked.

Authorities went door to door, launched air and ground searches and used dogs to try to track their scent.

Sheriff’s officials served a search warrant Wednesday at Valenzuela’s residence, and deputies were seen digging on the property before the bodies were found.

Valenzuela told investigators that he and the couple have been acquainted for the past two years and used methamphetamine together.

Babeu cautioned, however, that toxicology tests were needed to confirm that allegation. A message seeking comment from family members of the victims was not immediately returned Thursday.

Authorities said Valenzuela took meth to the home of Michael and Tina Careccia on the day before they went missing. Later in the day, they went to his home, where authorities say Valenzuela brandished a weapon during a fight.

Felix Rios Nunez, a friend and housemate of Valenzuela, told investigators he was awakened by the sound of gunfire, according to court documents.

Nunez said he saw a wounded Michael Careccia using a chair to try and get up and Valenzuela pointing a gun at Tina Careccia, who was on the floor. Nunez said he fled in fear after Valenzuela refused to give him the gun and pushed him.

Clark said he doesn’t know whether Valenzuela has an attorney.

Marla Francisco, who had a child with Valenzuela, said she no longer lives at the property searched by authorities and was shocked by the arrest.

"Who wouldn’t be?" Francisco said before hanging up the phone.

The abandoned car of Michael and Tina Careccia was previously found covered in dirt about a half-mile from their home in Maricopa, about 35 miles south of Phoenix.

There was no activity involving their phones, bank accounts, credit cards or social media accounts after they went missing, investigators said.

Tang reported from Phoenix.