Crime Writer
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January 14, 2019
DID A COWORKER’S OBSESSION LEAD TO MURDER? For years Kevin Prasad tried to persuade Thandar Seinn to go out with him, but she was engaged to someone else. Finally, police say, his infatuation drove him to kill

They were all friends—Kevin Prasad, Thandar Seinn and Mark Mangaccat— colleagues in the crowded terminals of San Francisco International Airport, where Prasad had worked for a private security firm, Mangaccat in aviation-support services and Seinn as a customer-service representative. Seinn and Mangaccat were engaged and had a little girl together, but that never seemed to deter Prasad from asking Seinn to spend time with him outside work.“It was just a crush,”recalls 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.”

Tragically, it may be that Prasad’s feelings for Seinn were far darker—and deadlier—than an innocent crush. On April 25, just days before the couple were scheduled to move to Las Vegas, where they planned to marry, Mangaccat, 31, picked Seinn up after her last shift at the airport. As he backed his car into the garage of their Daly City, Calif., home, a masked gunman approached and fired multiple times through the driver’s-side window, killing Mangaccat instantly. The following day Prasad, 32—along with alleged getaway driver Donovan Matthew Rivera, 26—was arrested. Both have been charged with first-degree murder. They pleaded not guilty and are being held without bail. “This was beyond infatuation,” says San Mateo County District Attorney Steve Wagstaffe. “He was obsessed with her. And once he realized she was about to move hundreds of miles away, he decided
to carry out his plan to bump her boyfriend out of the way.” For Seinn, who escaped injury in the attack, the idea that her coworker killed her fiancé is incomprehensible. “Mark is gone, and he was killed for no reason,” she says. “I can’t believe it happened. I can’t trust people anymore.”

But those who grew up with Prasad say there had long been hints of trouble below the surface. His former classmates at Natomas High School in Sac-ramento, where Prasad was voted “Most Unforgettable” during his senior year in 2004, describe him as “smart,” “dorky” and “desperate to fit in.” Some recall he had a habit of becoming infatuated with girls at the school that made them uncomfortable. “He was friendly but bizarre,” recalls Megan Parent, who insists she “wasn’t surprised” when she learned about his alleged role in Mangaccat’s murder. “He always had a little crush on me, and when I told him I didn’t feel that way, he got really upset, brought me some kind of costume-jewelry necklace and wrote me a letter saying we were meant to be together and I was going against God’s plan by rejecting him.”


By the time Prasad met Seinn and Mangaccat at San Francisco International in 2014, the couple were already dating, but that didn’t stop Prasad from asking Seinn to go out with him. Nor did the birth of Seinn and Mangaccat’s daughter in 2015. “He could be a little aggressive,” Seinn says of Prasad. “ButI workincustomer service,soI know how to deal with people like that. I’d tell him, ‘I’m a mother. I’ve got a family.’ ”

The young couple’s decision to relocate to Vegas (“They wanted to start a new life,” says Mangaccat’s mother, Myrna) pushed Prasad over the edge, investigators say. “As soon as he heard, he came up to me at work and started saying, ‘Why are you leaving? Don’t go,’ ” recalls Seinn. Homicide detectives were initially stumped over why someone would murder Mangaccat. “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,’ ” says Wagstaffe. “It ultimately led to getting to our two suspects.”

As Seinn grapples with the “emptiness” of losing the man she loved, she remains focused on keeping his memory alive for their daughter. “Every night when we go to sleep,” says Seinn, “she looks at his picture and says, ‘Goodnight, Daddy. Sweet dreams, Daddy.’ ”

©   Christine Pelisek