Boston bomber Tsarnaev arrives at Colorado 'Supermax' complex

FLORENCE, Colo., June 25 (UPI) -- Just one day after he was formally sentenced to die by a judge in Massachusetts, Boston Marathon bomber Dzhokhar Tsarnaev arrived at a maximum security prison in Colorado -- where the United States Penitentiary Administrative-Maximum Facility is located.

The prison complex, located in Florence, is also known as the "Supermax" complex -- where some of the nation's most notorious convicts serve, or have served in the past. Edmond Ross, a U.S. Bureau of Prisons spokesman, confirmed Tsarnaev's arrival at the prison Thursday, CNN reported.

The ADX facility is also colloquially called the "Alcatraz of the Rockies."

"As soon as they come through the door ... you see it in their faces," former warden Robert Hood said in CNN's report. "That's when it really hits you. You're looking at the beauty of the Rocky Mountains in the backdrop. When you get inside, that is the last time you will ever see it."

However, it wasn't initially clear whether Tsarnaev is actually being housed at the "Supermax" facility or a different high security prison that's part of the same complex.

Tsarnaev was convicted last month of taking part in the Boston Marathon bombings in 2013 -- along with his brother Tamerlan, who was killed in a police shootout days after the attack. Wednesday, after hearing from survivors and relatives of the three people killed in the bombings, Tsarnaev apologized for his role in the plot.

Numerous notorious criminals have been housed at the "Supermax" facility -- including 9/11 conspirator Zacarias Moussoui, 1993 World Trade Center plotter Ramzi Yousef and shoe-bomber Richard Reid.

It remains unknown, however, exactly where Tsarnaev will end up for his execution by lethal injection. It is possible he will be sent to the U.S. Penitentiary in Terre Haute, Ind., where Oklahoma City bomber Timothy McVeigh was put to death.