It had been 10 days since neighbors and family members had seen or heard from James and Marian Soares.

Most phone calls to their house went unanswered. Messages went unreturned.

When the couple’s son, James A. Soares Jr., did pick up the phone, he said his parents were out of the house, or on vacation, or too busy to talk. Then Marian missed a July 12 family reunion that she had helped plan.

The elder James Soares’ brothers, David and John, were worried. It just wasn’t like James and Marian to miss calls or go out of town without telling anyone.

On July 15, nine days after the Soareses were last seen at their Warren home, David and John Soares went to the Warren Police Department to report them missing. They said they believed their brother and sister-in-law were in danger.

More than a week later, the police would discover the bodies of James and Marian Soares in their backyard cesspool and would charge 24-year-old James Jr. in their double murder for allegedly bludgeoning his parents to death with a grub hoe.

A police affidavit filed this week in District Court, Providence, provides new details of the search for the Soareses and reveals the explanation James Jr. offered for his parents’ disappearance: a spat over infidelity by James Sr.

After learning that the Soareses were missing, the Warren police went to the family’s home at 14 Baltimore Ave. and spoke with James Jr.

James said he was worried about his parents, too, according to an affidavit signed by Detective David A. Annunziata.

Soares Jr. told police that he had last seen his parents on the morning of July 10. Later that day, he told the police, he had called home and spoke with his mom, whom he said was “extremely upset” after finding out that his father was cheating on her with another woman via the Internet or by phone.

Both his parents took off, Soares told the police. He said his mother called home on July 13, saying she was fine, staying with a friend in Massachusetts, and would be home the next day.

Soares Jr. was cooperative, letting the authorities do a “limited search,” as Annunziata put it, of the property and later going to the police station to give a formal statement.

But James Jr. couldn’t explain how his parents had gotten away when their three cars and motorcycle were still parked in the driveway. And he couldn’t explain why his parents had left behind all of their important belongings — cell phones, wallets, credit and bank cards, medications, Marian’s purse.

The police now allege that James Soares Sr., 60, and Marian, 53, had been dead for almost a week by the time officers spoke to their son.

On July 21, the Warren police were granted a warrant to search the home. They seized two blood samples from the floor and a rug, and a plastic jar of maggots collected from blood on the basement floor, according to court documents.

On July 25, the police issued a news release reporting the couple missing and took James Jr. into custody.

The next morning, James and Marian’s bodies were discovered in an unused cesspool behind their small, tan ranch house.

James Soares Jr. has been charged with two counts of murder. He remains held without bail at the Adult Correctional Institutions, in Cranston, since his arrest at home July 28. He is scheduled to appear Aug. 15 in District Court, Providence, for a bail-review hearing.

mwims@projo.com