DENVER (AP) - Attorney Jack Ebel testified before the Colorado Legislature two years ago that solitary confinement in a Colorado prison was destroying the psyche of his son, Evan. When Jack Ebel's longtime friend, Gov. John Hickenlooper, was interviewing a Missouri corrections official for the top prisons job in Colorado, he mentioned the case as an example of why the prison system needed reform. And once Tom Clements came to Colorado, he eased the use of solitary confinement and tried to make it easier for people housed there to re-enter society. Now authorities are investigating whether Evan Spencer Ebel, who was paroled in January, is linked to the assassination of Clements, who was shot and killed Tuesday night when he answered the front door of his house in a rural neighborhood. The bullet casings from that shooting are the same type as those found at the site of a bloody gun battle Thursday between Evan Ebel and Texas law enforcement officers that ended with Ebel being shot and killed, according to court records. The car Ebel drove matched the description of the one spotted outside Clements' house on the night of the prison director's death. Authorities also found a Domino's pizza delivery box in the trunk and a jacket or shirt from the pizza chain. Denver police say Ebel is now a suspect in the Sunday slaying of pizza delivery man Nathan Leon. Hickenlooper confirmed his relationship with Jack Ebel to The Denver Post and KUSA-TV Friday evening and then in a written statement Friday night. State records show Ebel donated $1,050 to the governor's 2010 campaign. But there's no indication that Hickenlooper's relationship with the Ebels played a role in the shooting. Hickenlooper denied having any role in Evan Ebel's parole. "Although Jack loved his son, he never asked me to intervene on his behalf and I never asked for any special treatment for his son," Hickenlooper's written statement said. State prisons spokeswoman Alison Morgan said Evan Ebel was paroled Jan. 28 as part of a mandatory process after serving his full prison term. He had most recently been sentenced to four years for punching a prison guard in 2008, according to state records. Hickenlooper said he never mentioned Ebel's name to Clements or anyone else connected with the prisons system. He said he only heard about the role of his friend's son Thursday night. "I didn't know Evan was out," the governor told The Denver Post and KUSA, adding that he called Jack Ebel after being told of the connection. He was distraught, he was devastated. I've never heard him so upset, and he's had some hard things in his life. Lt. Jeff Kramer of the El Paso County sheriff's office said Friday evening that he was unaware of the relationship between Hickenlooper and Ebel's father. Jack Ebel did not return multiple phone calls seeking comment. A federal law enforcement official said Ebel was a member of a white supremacist prison gang, the 211s. The official wasn't authorized to discuss the investigation publicly and spoke on condition of anonymity. Colorado officials wouldn't confirm Ebel's membership but placed state prisons on lockdown Friday afternoon. "There's been an inordinate amount of media attention on one threat group, and that has required additional security measures," Morgan said. The corrections department also was preparing for a Monday memorial service for Clements, she said. The 211 gang is one of the most vicious white supremacist groups operating in the nation's prisons, comparable to the Aryan Brotherhood of Texas, according to the Southern Poverty Law Center, which tracks extremist groups. Legal records show Ebel was convicted of several crimes in Colorado dating back to 2003. He said Ebel had a younger sister who died in a car accident years ago. Hickenlooper agreed that Evan Ebel had "a bad streak" that his parents had tried to correct. "The events of the past few days have been devastating for all involved," he said in the written statement. I am in shock and disbelief about how everything seems connected in this case. It makes no sense. Tom's death at the hands of someone hell-bent on causing evil was tragic in every way. It also now appears Tom's killer may have had another victim. Our hearts and prayers are with Nathan Leon's family as well. Contributing to this report were Associated Press writers P. Solomon Banda, Dan Elliott, Colleen Slevin, Alexandra Tilsley and Catherine Tsai in Denver; Thomas Peipert in Colorado Springs, Colo.; and Angela K. Brown in Decatur, Texas.