Sharon Louise Carr was born in Belize in 1979. She was raised in a challenging environment by her mother and stepfather. Sharon was one of four children and grew up in great poverty. She never knew her biological father. In 1986, Sharon's family moved to England and settled in Camberley, Surrey.

Soon after their move, her parents' marriage started to fall apart. There was a serious incident of domestic violence when Sharon's mother poured boiling fat over her stepfather. This incident caused both of her parents to be hospitalized with burns. Sharon's mother was charged with assault following this event.

At school, Sharon was initially seen as polite and helpful by her teachers. Her friends described her as sociable and said she liked to hang out with older boys. However, she occasionally displayed flashes of aggression. Over time, Sharon's behavior worsened. She became disruptive and attention-seeking, often having trouble with authority figures.

In 1990, her headteacher at Cordwallis Junior School contacted social services because of Sharon's behavior. She was briefly placed in foster care but returned home after just one month. By the time Sharon started secondary school, her mother had moved on and had a new partner with two daughters.

In the early hours of June 7, 1992, Sharon Carr stabbed 18-year-old Katie Rackliff to death as she was walking home from a nightclub in Camberley, England. Carr used a six-and-a-half-inch knife to stab Rackliff 32 times. The attack was brutal, with the knife piercing through Rackliff's ribs and heart, and causing severe injuries to her sexual organs. After the murder, Carr and some accomplices moved Rackliff's body to Farnborough, where they dumped it by a cemetery wall. The body was found later that morning by a group of boys.

Following the murder, police faced difficulties solving the case due to the violence of the attack. Investigators noted that the injuries resembled actions typically performed by an adult male, which complicated their understanding of the crime. Consequently, the case went unsolved for some time.

On June 7, 1994, exactly two years after Rackliff's murder, Carr attacked a classmate at Collingwood College. She stabbed a 13-year-old student in the back in a school restroom, causing a lung injury. The attack was interrupted by other students who came to help. When arrested, Carr expressed enjoyment about hurting animals and mentioned having killed a dog previously.

Initially held in a medical assessment center, Carr was charged with multiple counts of assault after attempting to strangle staff members. She was convicted in December 1994. Afterward, she was moved to several psychiatric and secure facilities due to her violent behavior. In mid-1996, while at Bullwood Hall, she began talking about the murder of Katie Rackliff in conversations and diary entries. These confessions ultimately led to her being charged with the murder in May 1996.

Carr was convicted of murder on March 25, 1997, after a month-long trial. The jury found her guilty after several hours of deliberation. This verdict made her the youngest female murderer in Britain, having been only 12 years old when she committed the crime.

After her conviction, Carr spent time in various institutions, including HM Prison Holloway and Broadmoor Hospital. Her behavior remained aggressive, and she often attacked staff and other inmates. Reports indicated that she sometimes expressed desires to harm others, including fellow inmates.

In 2004, Carr's defense team attempted to challenge her conviction and reduce her sentence, but these efforts failed. She continued to be a risk, leading to her placement in different facilities over the years. Despite being eligible for parole starting from 2011, Carr's applications for release were repeatedly denied due to her violent history and ongoing concerns about her behavior. As of August 2023, she was still in prison, considered a danger to the public.