Daryl Linnie Mack was born on August 28, 1958, in Reno, Nevada.

On October 28, 1988, the body of 55-year-old Betty Jane May was found in a boarding house in Reno, Nevada. Her neighbor discovered her body in her basement room. An autopsy revealed that Betty had been raped and strangled. The case went unsolved for twelve years.

On April 8, 1994, the body of 35-year-old Kim Parks was found in a motel room in Reno by a maid. Kim had been strangled with her own bra. She was known to work as a prostitute and had checked into the motel two days earlier. An autopsy indicated she was killed on April 7. Blood on a bedsheet in the room did not belong to her. Witnesses reported seeing Kim with Daryl Mack at the motel. Police took a sample of Mack's blood, which matched the blood from the crime scene. He was arrested and charged with murder.

Daryl Mack denied killing Kim Parks. He claimed they fought over money she took from him. Initially, he denied being at the motel. The DNA evidence, however, implicated him. In October 1994, he was found guilty of Kim's murder and sentenced to life in prison without parole.

While Mack was in prison, detectives reexamined the unsolved murder of Betty Jane May. DNA testing revealed that semen from her body and blood from her blouse matched Mack's DNA profile. In 2000, he was charged with the first-degree murder of Betty May. The state sought the death penalty this time. Mack chose to have his case tried by a panel of judges rather than a jury. He was found guilty and sentenced to death on May 15, 2002.

After his death sentence, Mack waived all appeals and stated he preferred execution to life in prison. His execution was scheduled for March 5, 2004, but was delayed due to legal issues. It was rescheduled to December 1, 2005, but was again put on hold by the Supreme Court of Nevada. In February 2006, Mack's execution was rescheduled for April 26, 2006.

On April 26, 2006, Mack was executed by lethal injection at Nevada State Prison. He had converted to Islam while in prison and spent his final hours reading the Quran. His last meal included a fish fillet sandwich, fries, and a soft drink. He was pronounced dead at 9:06 p.m. with his final words being "Allah is great, Allah is great."

Mack's execution made him the first African-American man executed in Nevada since the death penalty was reinstated in 1976. He was also the first inmate executed in the state based on DNA evidence. After the prison closed in 2012, he became the last person to be executed at Nevada State Prison. As of 2024, he remains the most recent person to be executed by the state of Nevada.