Anthony John Sully was born on January 2, 1944, in San Francisco, California. He grew up in Millbrae, where he completed his high school education. In the early 1960s, Sully met Elizabeth Ann, whom he married in 1965. Shortly after their marriage, he pursued a career in law enforcement and joined the Millbrae police department, becoming an officer in 1966. Sully served in the Patrol and Post Service from 1966 to 1974, maintaining a clean record and earning positive remarks from his colleagues.

However, during this period, his behavior began to change. In 1969, Elizabeth filed for divorce, citing four years of physical abuse. In 1974, Sully remarried, this time to a woman named Donna. Their marriage lasted only 15 months, ending due to Sully's continued physical abuse, which led to a court-issued restraining order preventing him from approaching Donna, her child, or her relatives. Donna recounted a disturbing incident in which Sully twisted the heads of her daughter's ducklings and threatened her child.

After leaving the police force, Sully started his own business as an electrical and construction contractor in the late 1970s, operating out of a hangar in Burlingame that he used as a warehouse. By the early 1980s, Sully's behavior had further deteriorated. He developed a heightened sexual interest in women and began associating with pimps and prostitutes, introducing himself as "Jack." He invested substantial amounts of money into creating an escort agency and started using drugs.

In 1982, Sully met Tina Livingston, a 32-year-old owner of a local escort agency. One of Livingston's employees, 24-year-old Gloria Fravel, was unable to repay a $500 debt and attempted to escape. In early February 1983, Livingston, along with another sex worker named Keli "Angel" Burns, tracked Fravel down in San Francisco and brought her to Sully's warehouse in Burlingame. Upon arrival, Sully propositioned Fravel for sex, which she refused. Sully then beat her and took her to the back of the warehouse, where he handcuffed her and suspended her from the ceiling. 

Over the next two days, Sully tortured and sexually assaulted Fravel, while Livingston and Burns remained in another part of the warehouse. During one of the torture sessions, Sully placed a hangman's noose around her neck. Fravel was mostly kept drugged with cocaine, but at one point, she managed to free herself from the gag and scream. Livingston and Burns failed to re-gag her, prompting Sully to strangle her with a rope. With the help of his accomplices, Sully placed Fravel's body in a car, and he and Burns drove off to dispose of it. During the trip, Fravel regained consciousness, so they stopped the car, and Sully killed her by hitting her head multiple times with an axe. They disposed of her body near State Route 35, where it was found on February 7. Sully reportedly kept a newspaper article about the discovery as a trophy and found it amusing that her body was discovered by a butcher.

Shortly after Fravel's murder, Sully asked Livingston to find a girl who was not a prostitute but would agree to provide sexual services for money. Livingston soon informed him about 19-year-old Brenda Oakden, a roommate of one of her escorts. Oakden, who occasionally engaged in prostitution under the name "Brenda Rule," was taken to Sully's warehouse in mid-February. There, Sully shot her in the back of the head with a .38 caliber revolver. After the murder, Livingston spread a rumor among Oakden's friends that she had left San Francisco.

Sully's next victims were Michael Thomas, a 24-year-old pimp, and his 20-year-old common-law wife, Phyllis Melendez. Thomas had a criminal record, and Melendez had been arrested for prostitution several times. In early 1983, Sully had an argument with Thomas. In April, Sully invited the couple to his warehouse and shot them both in the back of the head. He then placed the bodies of Oakden, Thomas, and Melendez in 55-gallon drums, filled them with concrete, and dumped them in Golden Gate Park. The bodies were found on April 29 by a patrolman.

In August 1983, Sully lured his ex-girlfriend, Barbara Searcy, to his warehouse under the pretense of offering financial help. Upon her arrival, he shot her in the back of the head. Sully then gave her clothes and belongings to Livingston, instructing her to erase a message from Searcy's answering machine, but Livingston failed to do so. Sully wrapped Searcy's body in plastic, and with Livingston's help, disposed of it near the Pulgas Water Temple, where it was found on August 18.

Sully's final victim was 24-year-old drug dealer Kathryn Barrett. In late August 1983, Sully invited her to his warehouse under the guise of buying cocaine. With the help of Michael Anthony Francis, Sully attacked Barrett, stabbing her and hitting her with a sledgehammer. Her body was found on August 19, wrapped in plastic bags in an industrial area of South San Francisco.

Sully was arrested on August 25, 1983, after investigators matched his fingerprints to those found on the barrels containing the bodies. During the investigation, additional evidence was found linking him to the crimes. Livingston confessed to her involvement and testified against Sully, leading to the arrests of Burns and Francis. Sully was charged with six murders and pleaded not guilty but was found guilty on all counts in 1986 and sentenced to death. His accomplices received various sentences, with Livingston receiving a lighter sentence in exchange for her testimony. Sully remained on death row at San Quentin State Prison until his death from natural causes on September 8, 2023, at the age of 79.