Thomas Jacob Sanford, the man accused of killing four people and burning down a Church of Jesus Christ of Latter-day Saints church in Grand Blanc, Michigan, was in relationship with a Mormon woman in Utah that ended painfully, a new report reveals. The New York Times reports that Thomas Sanford's ex-girlfriend was "extremely religious" and he felt pressure to join the church. His friend Peter Tersigni revealed that their relationship ended painfully and Thomas Sanford, when returned to Michigan, was in "rough shape".

He reportedly held a long-simmering hatred for the faith and was struggling with substance abuse, according to people close to him. Sanford's hatred grew out of a breakup he had with a girlfriend more than 10 years prior, his friends told the NYT.

ALSO READ: Michigan Church shooter Thomas Jacob Sanford, a decorated US marine, had a turbulent personal life? Check details

Chilling details about Thomas Jacob Stanford emerges

Kris Johns, a 44-year-old candidate for a Burton City Council seat, told the Detroit Free Press that he encountered an “extremely friendly” Sanford while knocking on people's doors during his campaigning last week. During their 20-minute conversation, Thomas Sanford opened up about his service as a US Marine in Iraq and his battle with drug addiction after returning home.

During discussion about religious belief, Johns told the outlet, the exchange took “a very sharp turn.” Sanford claimed to have dated a woman whose family was Mormon while he was living in Utah.

ALSO READ: Michigan Church shooting: Suspect Thomas Jacob Stanford's emotional Facebook post on his child's illness surfaces

Thomas Sanford's friends said he would rant about the LDS church and called the faith the Antichrist. He even took the chance to complain about the church to a politician canvassing homes in his neighborhood.

“It was very much standard anti-LDS talking points that you would find on YouTube, TikTok, Facebook. I just didn’t know what the next question was going to be,” Kris John told the Detroit Free Press. Sanford went on to call Mormonism “the antichrist,” he said. Johns claimed that when he first saw Sanford's image on TV and social media posts, he recognized him right away.

What changed in Thomas Jacob's life?

His friend Peter Tersigni told The Times that Sanford was a jolly person but deployment to Iraq with the Marines transformed him and turned him into a more serious person upon his return. According to Tersigni, a move to Utah and a habit of abusing methamphetamines further transformed his friend.

During his stay in Utah, Sanford reportedly fell in love with a woman who was part of the LDS. It's unclear exactly how involved he and the woman were, but what Tersigni did say is that the relationship ended in a way that left Sanford deeply hurt.

“Mentally [Sanford] was in rough shape," he told the paper.

ALSO READ: Candance Owens, who once called Charlie Kirk 'brother', skipped his Arizona funeral? The untold story behind her absence

He said it became very clear to anyone who would listen that Sanford had a problem with the LDS Church. “He got this whole fascination with Mormons, and they are the Antichrist, and they are going to take over the world,” Francis Tersigni, Peter's twin brother and another friend of Sanford's, told the Times.

Sanford was so obsessed with the church that the subject even came up at Peter's wedding. “All he could talk about was Mormons,” Francis said. “I was like, dude, nobody wants to hear about this stuff.”

Michigan church shooting

On the day of the mass shooting, Sanford drove his Chevy Silverado pickup truck into the church before opening fire on the congregants inside with an assault rifle. During the attack, he used an accelerant to ignite a fire that would ultimately destroy most of the building.

ALSO READ: Stimulus payment in October: US citizens set to receive the deposit soon? Check amount, eligibility and key details

Afterward, Sanford exited the church and began shooting at people attempting to flee. At one point, he fired through the windshield of a vehicle, narrowly missing the driver.

The FBI is still investigating the shooting, and considers the incident a "targeted act of violence." Investigators are still investigating what set Sanford off. Peter told the Times that he last talked to Sanford on September 18. Sanford reportedly asked Peter to help him build a deck, 10 days before Sanford attacked the church.