Born in 1981 in Tainan, Taiwan, Lin Yu-ju worked at a cabaret club, where she met Liu Yu-hang, a national badminton player. The couple married and operated a stinky tofu stand in Puli. Lin developed a gambling addiction, accruing significant debts from playing the Mark Six lottery. To alleviate her financial burdens, she devised a plan to murder close family members and collect on their life insurance policies.

On November 10, 2008, Lin pushed her mother, Hou Yueh-yun, down the stairs of their home in Tainan, resulting in a fatal head injury. She collected NT$5.06 million in insurance claims.​

In May 2009, Lin poisoned her mother-in-law, Cheng Hui-shen, by lacing her food with toxins. When Cheng was hospitalized, Lin tampered with her IV drip, adding antidepressants, ethanol, and methanol, leading to Cheng's death.​

Between June and July 2009, Lin attempted to murder her husband, Liu Yu-hang, using similar methods. After an initial failed attempt, she succeeded in poisoning him during a subsequent hospital stay.​

Authorities became suspicious due to the consecutive deaths and insurance claims. Investigations revealed Lin had also insured other relatives, indicating potential future targets. She was arrested in 2009 and, after a series of trials, was sentenced to death by the Supreme Court on June 14, 2013. Lin remains incarcerated at Taichung Women's Prison, awaiting execution.​