Who Is Considered the Most Dangerous Prisoner in the World?

Labeling any single person as the most dangerous prisoner in the world is difficult. Prisons around the world house individuals who are dangerous for very different reasons, such as extreme violence, organized crime leadership, terrorism connections, or their ability to influence crimes from behind bars.

Instead of one definitive “most dangerous” inmate, experts describe categories of prisoners whose actions, history, and influence make them exceptionally high-risk.

What Makes a Prisoner “Dangerous”?

Corrections agencies classify certain inmates as dangerous based on multiple factors:

• Extreme violence toward inmates or staff
• Leadership in organized criminal networks
• Ability to coordinate crimes from prison
• High escape risk or history of escapes
• Terrorism connections or mass-casualty crimes

These prisoners typically require:

• near-total isolation,
• restricted communication, and
• the highest-level security housing.

In the United States, this often means placement in a Supermax facility, such as ADX Florence.

Who is The Most Dangerous Inmate?

Thomas Silverstein is the most violent prisoner in the world. He began his criminal career with armed robberies in the 1970s and ended it in 2019 when he died in prison after 36 years of solitary confinement. For many years, Silverstein was considered the country’s most dangerous prisoner due to his crimes both in and outside of prison.

Outside of prison, he was a habitual criminal whose offenses were increasingly violent. By the age of 25, he was sentenced to 15 years in prison and was held at Leavenworth, where he formed ties to the Aryan Brotherhood gang. He was convicted in 1980 of murdering a fellow inmate who refused to aid the gang’s drug smuggling enterprise. Transferred to the maximum security unit at Marion, Illinois, he was then involved in the murder of a rival gang leader and the murder of a guard.

Marion was put on lockdown that lasted more than 20 years. Silverstein was transferred to maximum security in Atlanta with the caveat that he have “no human contact” in solitary confinement. He was eventually sent back to Leavenworth and later to ADX Florence where he died.

Other Highly Restricted or High-Risk Inmates

Several inmates worldwide are considered extremely dangerous based on their crimes or influence. At ADX Florence, the highest-security prison in the U.S., inmates have included:

• Ted Kaczynski (“Unabomber”) – domestic terrorist
• Dzhokhar Tsarnaev – Boston Marathon bomber
• Ramzi Yousef – 1993 World Trade Center bomber
• Zacarias Moussaoui – connected to 9/11 plot
• Terry Nichols – Oklahoma City bombing co-conspirator

These individuals are typically housed in near-complete isolation because of the harm they could cause if able to communicate freely.

Where Are the Most Dangerous Criminals Held?

Dangerous inmates are housed in maximum-security or Supermax facilities designed to eliminate escape attempts and limit communication.

Examples include:

• ADX Florence (U.S.) – considered the most secure federal prison
• HM Prison Belmarsh (UK) – holds high-risk terrorism offenders
• La Santé Prison (France) – known for its strict security
• Federal high-security units worldwide

These facilities rely on reinforced cells, restricted movement, intense monitoring, limited interaction with other inmates, and highly controlled visitation. This ensures inmates cannot harm others or direct external criminal activity.

FAQ

Who is currently considered the most dangerous criminal in the world?

There is no official global ranking. Different correctional systems classify inmates differently, and many of the most dangerous individuals are housed under strict secrecy. Experts instead refer to categories of inmates, such as high-risk terrorists, organized-crime leaders, and extremely violent offenders, rather than naming a single “most dangerous” person.

Why doesn’t the public always know where high-risk inmates are held?

For the most dangerous inmates, specific housing details can be restricted to protect staff, prevent escape attempts, and stop outside criminal coordination. Some Supermax prisoners may not appear in standard inmate searches for security reasons.

Can dangerous inmates ever be released from Supermax prisons?

In rare cases, inmates may be transferred out of Supermax units if they demonstrate years of stable behavior. However, many high-risk offenders remain there permanently due to life sentences, ongoing threats, or national security concerns.

Are there dangerous inmates outside the United States?

Yes. Other countries also operate high-security or Special Management Units that house terrorism suspects, cartel leaders, serial offenders, and individuals considered extreme security risks. Facilities such as HM Prison Belmarsh in the UK or La Santé Prison in France hold inmates classified at high risk.

Can the public look up an inmate’s criminal history?

In most cases, yes, many jurisdictions provide access to public court records or inmate databases. However, details related to high-security classifications, internal investigations, or the daily management of dangerous inmates may remain confidential for safety reasons.