Unabomber Ted Kaczynski, who terrorized the United States with a series of mail bombings in the 1980s and 1990s, has been found dead in his prison cell. According to prison officials, Kaczynski, 79, was found unresponsive in his cell at the maximum-security facility in Florence, Colorado on Wednesday morning. The cause of death is believed to be suicide.

Kaczynski, also known as the “Unabomber,” was a former mathematics professor who carried out a series of bombings that killed three people and injured 23 others. He conducted a vendetta against modern technology and industrial society, and his targets included universities and airlines.

Kaczynski evaded capture for nearly two decades before he was finally apprehended in 1996. In 1998, he pleaded guilty to the bombings and was sentenced to life in prison without parole.

Since then, Kaczynski has been held in the Administrative Maximum Facility, or “Supermax,” in Florence, Colorado. The prison is known for its strict isolation and high-security measures.

Kaczynski’s death comes just weeks after an HBO docuseries about his crimes and capture was released. The series, titled “The Unabomber: In His Own Words,” featured audio recordings of Kaczynski’s own words and interviews with investigators and survivors of his attacks.

In a statement, the Federal Bureau of Prisons said the death is being investigated by the FBI’s Denver field office. “No staff or other inmates were injured, and at no time was the public in danger as a result of this incident,” the statement said.

Kaczynski’s death has reignited the debate over the use of solitary confinement and other forms of extreme isolation in prisons. Critics argue that such measures can cause serious mental health problems and may contribute to inmate suicides, while supporters say they are necessary to maintain order and safety in prisons.

The death also raises questions about the legacy of one of the most notorious criminals in U.S. history. Despite his heinous acts, some have praised Kaczynski’s ideas and criticized the society that produced him. Others have condemned his violent tactics and called for greater understanding of the harms caused by his bombings.