Blanca Turrubiate-Simpson, who worked for the Murdaugh family for more than a decade, says one detail finally convinced her that Alex Murdaugh had murdered his wife, Maggie, and son, Paul.

In an exclusive interview with People, the longtime Murdaugh employee discussed the details that led her to believe that the now disgraced South Carolina lawyer killed his wife and son in 2021. Turrubiate-Simpson wrote that she long trusted Alex and loved the family she served.

“There was no universe in which Alex could have committed these crimes,” she wrote in her new memoir, “Within the House of Murdaugh: Amid a Unique Friendship – Blanca and Maggie,” co-written with Mary Frances Weaver, which will be released this month.

But after the June 7, 2021, killings at the Murdaughs’ Moselle estate in South Carolina, small inconsistencies began to trouble her.

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The morning after the murders, Maggie’s Mercedes SUV had been parked in an unusual spot, something Turrubiate-Simpson said Maggie never did.

Pajamas and a pair of underwear were laid out neatly in the laundry-room doorway, even though Maggie “never wore underwear to bed,” Turrubiate-Simpson said.

“I knew automatically that wasn’t her,” she told the outlet.

In Alex’s bathroom, she found a puddle of water, a towel and a pair of khaki pants she recognized from the morning before. She also noticed that the shirt Alex wore in a Snapchat video that day disappeared and was never seen again.

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Months later, Alex asked her if she remembered him wearing a Vineyard Vines shirt on the day of the murders.

“You remember what I was wearing that day,” she remembers him telling her, she writes. “You know, the Vinny Vines [Vineyard Vines] shirt.”

Turrubiate-Simpson said she did not, saying she remembered ironing a seafoam green polo. The question, she said, felt like an attempt to change his story from that night.

“One thing was for sure,” Simpson writes. “He was lying.”

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Her turning point came during Alex’s 2023 murder trial, when she saw police bodycam video showing a beach towel on the front seat of his car.

The longtime housekeeper said she had washed, dried and folded that towel earlier that day and placed it on a high shelf in the laundry room.

“When I saw that towel in his car, I said, ‘Oh my God. He did it,’” she told People.

She speculates in the book that Alex hosed himself off near the kennels and either changed there or back at the house.

Alex, she speculates in the book, “went to the laundry room, grabbed the towel to finish drying himself, and possibly took the freshly washed T-shirt hanging there.” 

Alex told police he had been sleeping in the main house at Moselle when Maggie and Paul were shot. He said he went to his parents’ house in nearby Varnville to check on his father, Randolph Murdaugh, 81, who died three days after the murders. 

Alex said that when he returned to Moselle at 10:07 p.m., he found the bodies of his wife and son and called 911.

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Alex Murdaugh was convicted in March 2023 of killing his wife and son and sentenced to life in prison without parole.

Fox News Digital has reached out to Alex Murdaugh’s attorney, Dick Harpootlian, for comment.