Former Marine's Murder Exposes Wife's Affair with Pastor

Sept. 26, 2013 — -- Family man and former Marine Randy Stone was a pillar in his community of Independence, Mo.

Stone owned an insurance business, where his wife of 19 years, Teresa Stone, also worked with him. Randy and Teresa had known each other since childhood, but lost touch after Randy enlisted in the Marines at 18. The two married when Randy returned from service.

"He worshipped Teresa, she meant everything to him," Robert Davis, Randy's good friend and fellow insurance agent, told ABC News' "20/20." "We couldn't be at any sort of an event, away from work, without him constantly calling her, ...or Teresa calling him."

The couple had two children, Michael and Miranda, who were baptized at the church Randy and Teresa were married at: New Hope Baptist Church, in Independence, Mo.

"Randy was... there every ...Sunday night, Wednesday night, and if there was an activity...he was there," Randy's mother, Clara Stone Koehler told "20/20." Randy drove church buses, advised the church on financial matters, and taught Sunday school, and Teresa sang in the choir and helped in the kitchen.

New Hope Baptist's Pastor David Love was even Randy's best friend and spiritual advisor. With family, church and a tight-knit circle of friends it seemed Randy and Teresa were leading a righteous, pure, even devout life.

"He told me he would love her until the day he died, and believe me, he did," Koehler said.

On March 31, 2010, Randy, 42, was found shot and killed in his insurance office. Police investigators found no sign of struggle, and cash had been left on his desk. They quickly came to believe this was not a robbery, but a homicide.

Investigators Have Their Suspicions

Hundreds turned up for Randy's funeral, listening to Randy's pastor, David Love, give a stirring, heartfelt eulogy.

"We weep not just because of the separation of our loved one but because of the questions that death brings," Love can be heard saying during a police recording of his eulogy for Randy. "Questions like why, why him? Why now?"

Detectives were among the mourners at Randy's funeral, recording in the church because they believed the killer might also be in attendance.

They also found evidence that they hoped would point to the killer.

"One of our people went through … a trash canister next to Teresa Stone's office desk, and there was ... a one-page letter that had been torn up in multiple pieces," Detective Keith Rosewaren told "20/20."

The letter appeared to detectives as a happy birthday or love letter, with phrase such as, "Happy Birthday Love. I am not in control of things yet but when we are fully together your birthday will always be exciting." Police determined that the letter was written in handwriting that was different from Randy's writing samples.

When police brought Teresa in for questioning at their station, she gave officers a well-documented alibi, complete with exact times and receipts.

"No one who wasn't preparing for that, would be able to recite their whereabouts down to the minute… the way Teresa Stone did," Molly Hastings, David Love's attorney told "20/20."

However, when detectives asked Teresa about the torn up note they found in her trashcan, she didn't have an answer.

Police left Teresa alone in the interrogation room, where their camera recorded her saying, "Oh great. I forgot about that."

When police returned, Teresa explained that the note was from a secret admirer, but detectives were already suspicious.