Crime Calif. Triathlete Who Competed in Ironman Races Is Killed by Ex-Boyfriend in Murder-Suicide Mary Knott was training for three marathon swims in 2021 By Chris Harris Chris Harris Twitter Chris Harris has been a senior true crime reporter for PEOPLE since late 2015. An award-winning journalist who has worked for Rolling Stone and MTV News, Chris enjoys prog rock, cycling, Marvel movies, IPAs, and roller coasters. People Editorial Guidelines Published on February 22, 2021 10:41 AM Share Tweet Pin Email Mary Knott. Photo: Mary Knott/Blogspot Authorities in southern California have confirmed a 44-year-old veterinarian who competed in triathlons all around the world was murdered on Feb. 13 by her 33-year-old ex-boyfriend, who then killed himself. The San Diego Union-Tribune, KSWB-TV, and KGTV report that Mary Knott was killed the day before Valentine's Day by her former boyfriend, Hilton Williams. Investigators found the both bodies inside an apartment in Carlsbad on Feb. 14. Police were dispatched to the apartment after receiving a tip from authorities in Australia, according to the reports. An Australian relative of Williams' contacted police there after receiving a text message from him saying he had murdered Knott and was about to kill himself. After getting no response at the front door, officers forced their way into the apartment, where they found the victim and her killer. It is unclear at this point how Knott and Williams died. A motive has also not been publicized. Knott competed in more than 20 Ironman competitions, and blogged about her experiences. She also once competed in the fabled Ironman World Championship in Kona, Hawaii, finishing in second place. Williams was also an endurance athlete. Want to keep up with the latest crime coverage? Sign up for PEOPLE's free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases. According to her friend and triathlon coach, Hillary Biscay, Knott was an "incredible human" who was training for three marathon swims in 2021. "She was a daughter, sister, aunt, devoted animal mom, and a veterinarian," Biscay wrote in an email to the Union-Tribune. "She had many gifts and she shared them generously." Biscay added: "Mary was everything from a lifeline to a major source of motivation and inspiration for her athletes — and likewise for her friends — many of whom were one [and] the same. [Her family and friends] will do everything we can to carry on her work and her legacy as this tragic loss leaves a gaping hole for so many."