Thandar Seinn and her fiancé Mark Mangaccat were planning to start a new life. The couple, who met at work at the San Francisco International Airport, were excited to move with their young daughter from California to Las Vegas where they planned to get married.
“It was a new chapter. Everything was changing,” Seinn tells PEOPLE. “We wanted to create our own life.”
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But their plans were shattered on April 25, 2018.
That evening, Mangaccat picked up Seinn after her final shift at the airport before the couple’s relocation. As he pulled into the garage of their Daly City home, a masked gunman ambushed the car, firing multiple times through the driver’s side window, killing Mangaccat instantly.
Homicide detectives were initially stumped over why someone would murder 31-year-old and reached out to Seinn for help.
Seinn initially had no idea but soon told police about a co-worker who had, what she thought at the time, was an innocent crush on her.
“Almost as an afterthought [Seinn] said, ‘There is a fellow at work who has had an interest in me, but he would never do that,’ ” San Mateo County District Attorney Steve Wagstaffe tells PEOPLE. “It really flowed from the fact that, well, there is this guy at work and that’s what led to these guys.”
RELATED: Police: Calif. Man Who Had Crush on Coworker Allegedly Killed Her Fiancé
The following day, police arrested airport security worker and suspected gunman Kevin Prasad and alleged getaway driver Donovan Matthew Rivera, 26, and charged both with first-degree murder. The men have pleaded not guilty and are being held without bail, pending a preliminary hearing in March.
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Prasad’s attorney declined to comment and Rivera’s attorney did not return multiple calls for comment.
Wagstaffe says Prasad was “obsessed” with Seinn.
“Once he realized she was about to move hundreds of miles away,” Wagstaffe says, “he decided to carry out his plan to bump her boyfriend out of the way.”
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Seinn says she is still shocked about the gruesome slaying and never suspected that 32-year-old Prasad, who had unsuccessfully asked her out a few times, would resort to murder.
“It was just a crush,” says Seinn. “He’d say things like, ‘Don’t you want to go out with me?’ Mark knew about it, but neither one of us paid too much attention to it.”
Today, Seinn raises her daughter, 3, with Mangaccat’s parents at that same Daly City home. Every day, she thinks about Mark.
“I wish it could be a bad dream,” she says. “But it’s not. I am empty. I only think of Mark. He should be here. It is a killing for nothing. There was no reason.”