Malcolm George Baker was born on 13 August 1947 in Sydney, New South Wales, Australia. He worked as a motor mechanic and resided in Terrigal, a coastal town in New South Wales. Baker had a history of volatile relationships and was known to have a temper. Prior to the events of 1992, he had been in a relationship with 23-year-old Kerry Gannon, which ended approximately six weeks before the shootings. Following the breakup, a court had ordered Baker not to contact Gannon, and authorities had revoked his firearms license and confiscated his weapons after he allegedly harassed her.

On the evening of 27 October 1992, Baker embarked on a shooting spree across three towns on the Central Coast of New South Wales.​

Terrigal (9:12 p.m.): Baker arrived at the apartment of his ex-girlfriend, Kerry Gannon, which she shared with her 18-year-old pregnant sister, Lisa Gannon. He used his shotgun to smash the front window and shot 22-year-old Christopher Gall, a friend of the sisters, in the face, severely injuring him. Baker then entered the apartment, shooting and killing Kerry and Lisa. Their father, Thomas Gannon, who was visiting, was found dead in the street outside. Efforts to save Lisa's unborn child were unsuccessful.​

Bateau Bay (Approximately 9:30 p.m.): Baker drove to the home of his 27-year-old son, David Baker, and shot him in the back of the head, killing him. David's body was discovered in the backyard of the residence he shared with his partner and child.

Wyong (Shortly before 10:00 p.m.): Baker proceeded to the home of Ross Smith, 35, and Leslie Read, 25. He shot and killed Smith, who was found in the bathtub, and critically injured Read, who died two hours later in the hospital. Baker and Smith had previously had a confrontation over a failed business deal.​

Surrender (11:00 p.m.): Baker turned himself in at the Toukley police station, handing over his sawn-off shotgun.​ He was charged with six counts of murder and one count of attempted murder. On 6 August 1993, Baker pleaded guilty to all charges and was sentenced to six consecutive life sentences without the possibility of parole.

In 2001, Baker became one of the first inmates housed in the High-Risk Management Unit at Goulburn Correctional Centre. He remained incarcerated there until his death on 22 June 2024, at the age of 76.​