A killer bank robber somehow strangled an inmate in another cell with a bedsheet ... penalty for Petty. ADX Florence is widely-regarded as the world's most secure prison for America's most ...

Petty, 56, was serving a life sentence at ADX Florence, the highest-security ... He was also convicted in 2015 of attacking ...

A man at the supermax prison in Florence who has been charged with killing another inmate may face the death penalty, the U.S. Department of Justice said on Thursday.

Petty, 56, was serving a life sentence at ADX Florence ... in 2015 of attacking two prison librarians and a case manager who were delivering books to his cell, prosecutors said.