Lloyd Maurice Crosbie was born on 16 April 1982 in Wangaratta, Victoria, Australia. He was the youngest of five children in a family marked by domestic violence. His parents separated when he was five, leading to periods in foster care. Crosbie's upbringing involved exposure to violence; he and his older brothers reportedly tortured animals and watched violent films. One brother was institutionalized after a murder verdict of not guilty due to mental impairment, while another served a lengthy sentence for attempted murder. Crosbie expressed a desire to commit murder to "reunite" with his incarcerated siblings.

In August 2000, police responded to Crosbie's home after neighbors reported him destroying property. He was taken to Latrobe Regional Hospital, where a police officer noted Crosbie's deep-seated anger and fixation on killing someone. In late 2000, Crosbie began a relationship with 18-year-old Melissa Joy Maahs. They moved in together and, by April 2001, were living with Melissa's mother, Kaye Lucy Maahs, in Morwell, Victoria.

On 18 August 2001, around 3 a.m., Crosbie attacked Melissa Maahs as she slept, stabbing her in the head with a skinning knife. As she screamed and attempted to defend herself, her mother, Kaye, intervened. Crosbie assaulted Kaye with various household items, including porcelain ornaments, a frying pan, and an iron. He alternated attacks between the two women, ultimately killing both. Afterward, he sexually assaulted Melissa's corpse, placing pornographic magazines on her back during the act. He then staged the scene to resemble a burglary and fled to Wangaratta.

Police arrested Crosbie on 20 August 2001. He confessed to the murders but could not provide a clear motive, stating, "I don't know. I just did."

In March 2003, Crosbie pleaded guilty to both murders. The court described the killings as "callous and brutal," noting Crosbie's sexual sadism and fascination with death and destruction. He was sentenced to two consecutive life terms with a non-parole period of 30 years. Due to threats from other inmates, he remains in protective custody.