Lê Thanh Vân was born on December 5, 1956, in Saigon, South Vietnam. She was the second child in a family of eight children. Her father worked as a drainage worker, and her mother was a midwife. Tragically, her older brother died when he was a child, which made Lê the oldest of the seven surviving siblings.

From a young age, Lê showed a strange and distant personality. She was often unruly and got into arguments with her family. There were even reports of her being violent toward family pets. Lê completed school until the 12th grade but dropped out halfway through. In 1975, she enrolled in the Military Medical School of Dentistry.

Later, Lê faced legal troubles. She was arrested for trying to cross the border illegally and spent 16 months in a re-education camp. After she got out, she worked various jobs to support herself. In December 1979, she was arrested again in District 10 for pretending to be an army captain. This time, she received a short prison sentence.

Her issues with the law continued in March 1990, when she was arrested once more in District 5 for forgery and theft. After serving 18 months in prison, she found a job as a caretaker for the Chung family. Unfortunately, this job did not end well. On October 24, 1992, members of the family were hospitalized after eating chicken noodles she prepared. One family member, Mrs. Bùi, died from poisoning. However, there was not enough evidence to charge Lê with murder at that time, and she was convicted of fraud instead.

Lê had been married twice. Her first husband was Nguyễn Quang Mễ, whom she married in 1984. They had two children together, but he died in 1989 under unknown circumstances. She remarried a man named Lê Văn Minh in 1991, but he died suddenly the next year in the hospital.

At the end of 1997, Lê Thanh Vân started her criminal activity when she worked at a hospital in Ho Chi Minh City. She met Đinh Văn Khảm and impressed him by claiming to be a dental specialist. After moving to Long Khánh and marrying an employee named Dìu Dãnh Quang, her actions turned deadly. On January 3, 1998, Vân poisoned her mother-in-law, Võ Thị Lý, with cyanide. Lý collapsed and later died after being rushed to the hospital. Vân took Lý's money before returning to the family.

On June 2, 1998, Vân targeted Quách Cẩm Minh, a security guard. She poisoned him with alcohol, leading to his death after he was taken to a medical center. A month later, she poisoned her mother-in-law, Hín Văn Dính, for inheritance money. On February 24, 1999, she poisoned her brother-in-law, Lê Văn Cẩm, while pretending to help him with his medication. He died later in the hospital.

Vân's next victim was Hồ Thị Mộng Đào, whom she poisoned during lunch. Although Đào was initially treated and released, Vân poisoned her again and she died that night. Vân continued her murder spree by poisoning company director Võ Hữu Khiêm for his motorbike.

In 2000, under the alias Lee Ly Lan, Vân poisoned Nguyễn Thanh Sơn with tainted rice vermicelli. In June of that year, she killed Nguyễn Văn Đông and Trần Thị Xinh with poison as well. The police began to investigate her when they discovered her involvement in these deaths. On January 15, 2001, Vân had been released due to lack of evidence despite being found with cyanide.

She continued to kill in 2001. In March, Vân poisoned her friend Nguyễn Trung Dzu during a visit. Dzu fell ill and died, after which Vân stole his money and phone. Later that year, she murdered Trần Văn Khôi and Vi Thị Thanh for their motorbikes, all while using fake identities and credentials to deceive others.

By October 15, 2001, the police arrested Vân for illegal possession of poison. The investigations revealed a pattern of murders and robberies linked to her. In early 2003, Vân confessed to killing at least 13 people.

Her trial started on August 25, 2004, and it became a significant case in Vietnam’s history as it was the first time a woman faced murder charges for such a high number of victims. Vân denied her guilt and fainted during the proceedings. On August 28, prosecutors sought the death penalty for her. Ultimately, she was found guilty and sentenced to death for her crimes.

After several appeals, Vân's sentence was upheld. She requested a pardon from the president, which was denied. On October 26, 2005, Lê Thanh Vân was executed by firing squad.