DENVER (CBS News) -- 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.
Wise County Sheriff David Walker in Texas spoke to CBS News correspondent Anna Werner about what the car could tell the authorities. "I think the vehicle will lead us to where he's been," he said. He also added that it is unknown why he was in Texas.
Hickenlooper confirmed his relationship with Jack Ebel to The Denver Post and KUSA-TV Friday evening, and 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 that he had any role in Evan Ebel's parole. State prisons spokeswoman Alison Morgan said 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," said the governor, adding that he called Jack Ebel and told him about 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.
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.
Founded in 1995 to protect white prisoners from attacks, it operates only in Colorado and has anywhere from between a couple hundred to 1,000 members, senior fellow Mark Potok said Friday.
Legal records show Ebel was convicted of several crimes in Colorado dating back to 2003.
Scott Robinson, a criminal defense attorney and media legal analyst, represented Ebel in 2003 and 2004. He said Ebel had been sentenced to a halfway house for a robbery charge in 2003 before he was accused in two additional robbery cases the following year that garnered prison sentences of three and eight years.
"I thought he was a young man who was redeemable, otherwise I wouldn't have taken the case," Robinson said, saying he didn't recall the details of the case.
Robinson said he knew Ebel before he got in trouble. He said Ebel had a younger sister who died in a car accident years ago.
Vicky Bankey said Ebel was in his teens when she lived across from him in suburban Denver until his father moved a couple of years ago. She remembers seeing Ebel once jump off the roof of his house. "He was a handful. I'd see him do some pretty crazy things," she said.
"He had a hair-trigger temper as a kid. But his dad was so nice," Bankey said.
Hickenlooper agreed that Evan Ebel was dangerous. "He just had a bad streak," the governor said. "Jack and his wife did everything they could. ... Nothing worked."
Meanwhile, Kaufman, Texas police chief Chris Aulbaugh said Friday the FBI is checking to see if the January shooting death of Kaufman County Assistant District Attorney Mark Hasse is connected to Tuesday's killing of Clements. Hasse was killed about 100 miles away from where Ebel died.
Aulbaugh calls the investigation routine for attacks that appear similar. Both targeted law enforcement officials. Authorities have investigated whether Hasse's death could be linked to a white supremacist gang.