Mullins was born on June 28, 1961, in Memphis, Tennessee, as one of seven siblings. In his early years, he lived with his mother, Ida, before relocating to West Memphis to stay with his father. Reports suggest that Mullins may have been illiterate. He struggled academically, failing first grade and frequently missing school, with his IQ test scores ranging between 59 and 69. Mullins dropped out of school in the ninth grade in 1977. Allegedly, three years later, he witnessed his mother's fatal shooting and claimed she died in his arms, although the Memphis police have no records of her death. His father also passed away around this time under different circumstances.

Following these traumatic events, Mullins made several suicide attempts but survived each one. He later disclosed to a psychiatrist that he experienced hallucinations and was subsequently diagnosed with schizophrenia and bipolar disorder. Although prescribed various medications, Mullins often did not adhere to his treatment, leading to multiple stints in rehab. He primarily lived with his sister, Janice, and his brother, William. Mullins initially worked for William's landscaping business before securing a job in concrete construction, which involved traveling to Texas and Louisiana. Over time, Mullins developed a drug addiction.

Over a span of 13 years, Mullins committed brutal assaults on four women, resulting in the deaths of three. His first victim was Beatrice Marie Cole, a 43-year-old homeless former mental patient. On May 28, 1999, outside the former National Bank of Commerce, Mullins attacked Cole, raping her and then fatally smashing her head with a brick. He attempted to disguise her body as a sleeping homeless person by covering it with a yellow blanket. Her body remained undiscovered for about five hours until maintenance workers, mistaking her for a sleeping vagrant, uncovered her and realized she was dead. Cole was buried by her family on June 5 in Marion Memorial Cemetery.

Mullins's second attack occurred over eight years later, on April 18, 2008, when he assaulted 79-year-old Jessie Lee Maples in Morningside Park. Maples was found and taken to the hospital, where she spent 21 days in intensive care before being moved to a private nursing home. The severity of her injuries required care in a private facility until her death in November 2012, though her death was not officially ruled a homicide.

In early August 2011, Mullins attacked 46-year-old Valerie Ector, using a concrete block to fracture her skull and break her jaw. He then dragged her body over 100 feet across a parking lot, covering it with a blanket to make it appear as if she were a sleeping homeless person. However, an employee discovered the body after following a trail of blood.

Mullins's final attack took place on June 6, 2012, when he used a brick to murder 67-year-old Gwendolyn Jackson in Downtown Memphis. Her body was found near St. Mary's Catholic Church.

Following Jackson's murder, Mullins was arrested after his fingerprints were found on a paper bag near the crime scene. DNA evidence linked him to the other murders, and he was also a suspect in the assault on Maples. In 2013, after a mental evaluation, Mullins was indicted for three murders and held without bail. On December 5, 2014, he pleaded guilty to three counts of first-degree murder and three counts of aggravated rape, receiving three life sentences and additional terms of 15 years for the rape charges, to be served concurrently.

In January 2015, Mullins was charged with attempted first-degree murder and aggravated rape related to the 2008 attack on Maples. On May 1, 2015, he was sentenced to 50 years in prison for this assault.