David Gilroy was a Scottish businessman and former colleague of Suzanne Pilley, working at the same infrastructure company in Edinburgh. He was reportedly married at the time and had been having an affair with Suzanne, which ended prior to her disappearance. Following the breakup, Gilroy displayed signs of obsessive and controlling behavior, including repeatedly contacting and attempting to reconnect with Suzanne.

Before the crime, Gilroy was seen as an ordinary professional, with no violent criminal history. However, those close to the case later described his behavior as manipulative and jealous, particularly after Suzanne ended their relationship.

On May 4, 2010, Suzanne Pilley left her home on Whitson Road, Edinburgh, to attend work at Infrastructure Managers Ltd on Thistle Street. She never arrived and was subsequently reported missing. A major missing person investigation was launched, which later became a murder inquiry. Gilroy was arrested on June 23, 2010, and charged with her murder.

The prosecution presented a case built entirely on circumstantial evidence, as Pilley's body was never found. Evidence included Gilroy's sudden cessation of contact with Pilley after her disappearance, injuries on his body consistent with a struggle, and CCTV footage tracking his movements to Argyll, where he is believed to have disposed of Pilley's body. Cadaver dogs indicated the presence of human remains in the boot of Gilroy's car and areas of the office basement.

On March 15, 2012, after a 24-day trial, Gilroy was found guilty by a majority verdict of murdering Suzanne Pilley and attempting to defeat the ends of justice. He was sentenced to life imprisonment with a minimum term of 18 years. The case was notable for being one of the few in the UK where a murder conviction was secured without the victim's body being found.

Despite multiple appeals, Gilroy continues to maintain his innocence and has refused to disclose the location of Pilley's body. In 2025, the Scottish Government proposed "Suzanne's Law," which would allow parole boards to consider a prisoner's refusal to reveal the location of their victim's body when deciding on parole eligibility.

As of now, Gilroy remains incarcerated, and the search for Suzanne Pilley's remains continues, with authorities focusing on areas in Argyll where Gilroy's car was tracked following her disappearance.