A 62-year-old man arrested last week at a Southern California nudist resort in connection with the disappearance of his neighbors has been charged with two counts of murder, authorities announced Tuesday.

Human remains believed to be those of 73-year-old Stephanie and Daniel Menard, 79, were found Friday under Michael Royce Sparks’ house at Olive Dell Ranch in Redlands following an hours-long SWAT operation, according to investigators. Sparks was arrested a day earlier at the San Bernardino County nudist resort on suspicion of murder in the disappearance of the Menards one week earlier.

The remains, which have not been identified by the coroner, were found by a fire department confined space search-and-rescue team in bags in a concrete basement under Sparks’ house following the SWAT operation. A tip from someone at the ranch led authorities to the residence, which was destroyed by an armored SWAT vehicle during the standoff with the armed suspect.

Sparks was found underneath the home and armed with a rifle, which misfired in a suicide attempt, said Redlands Police Chief Rachel Tolber. Sparks’ arrest came after several attempts to contact Sparks inside his home. When there was no response, law enforcement officers used an armored SWAT vehicle to tear down the house.

Tolber said Tuesday that the remains found under the home are believed to be those of the Menards. It was not immediately clear how long the remains were under the house.

“We’re mourning with the community over the homicides of Dan and Stephanie Menard,” said Redlands Police Chief Rachel Tolber.

An initial court date was set for Sept. 4. In addition to the two counts of murder, Sparks also faces a special circumstance allegation of multiple murder, which makes him eligible for a sentence of life without parole.

His arrest came nearly a week after the disappearance of the Menards, who were reported missing Aug. 25 by a friend. They were last seen at 10 a.m. a day earlier at their home in the 26000 block of Keissel Road. Their unlocked car was found nearby. Stephanie Menard’s purse was found at their home, as were the couple’s cellphone.

Their dog Cuddles also was missing. At a Tuesday news conference, authorities said there were no updates regarding the location of the dog.

Investigators have said there was evidence that led authorities to believe the couple’s remains were still on Sparks’ property about 70 miles east of Los Angeles. A cadaver dog “alerted” on at least one body at the property, Redlands Public Information Officer Carl Baker said during a news conference last week at the location.

Details about a motive or a possible cause of death were not immediately available. Residents said they believe Sparks lived alone.

“In this case, we believe that we can move forward and prove that Mr. Sparks is responsible for both (deaths),” said San Bernardino County District Attorney Jason Anderson.

A woman who said she called 911 Aug. 25 to report the missing couple said she was concerned after they didn’t show up for a regular Friday potluck and karaoke night at a neighbor’s house. On Sunday, Irene Engkraf said she was on her way to church when they noticed the abandoned car. They checked the house and went to church, but there were no signs of the Menards at either location.

She then entered the Menard’s house and, after finding the purse and cellphones, called 911, she said. There were no signs of a disturbance.

The Olive Dell website describes the ranch as a residential RV park and family friendly nudist resort.