A prison conspiracy?
Since Tuesday, investigators looking into Clements' killing have told reporters they are considering numerous angles.
One is that Ebel, a former member of the 211s -- a white-supremacist prison gang -- might have conspired with other inmates to kill Clements, Paula Presley of the El Paso County, Colorado, sheriff's department said.
The Department of Corrections told investigators that Ebel was a prison gang member, she said on CNN on Friday.
Clements earned widespread recognition for not only prison reforms but for a crackdown on prison gangs, including the 211s.
Citing media coverage of the shooting and its possible connection with the the 211s, authorities locked down Colorado's prisons on Friday, said state Department of Corrections spokeswoman Alison Morgan.
"We are on full lockdown over the weekend, no visitation or volunteer programs," she said.
Suspect's troubled past
As authorities look for possible links in the case, a troubling portrait began to emerge of Ebel.
By all accounts, Ebel came from a privileged upbringing. His father, Jack Ebel, an attorney and former oil executive, counts Colorado Gov. John Hickenlooper among his friends.
"When I first came out to Colorado 30 years ago, he and I worked in the same oil company," Hickenlooper told reporters Friday.
The governor described Jack Ebel as "generous to a fault," but said the son "had a bad streak."
"We knew his son growing up that he just had a bad streak," Hickenlooper told CNN affiliate KUSA. "I think Jack, his wife, they did everything they could."
Hickenlooper, who did not go into details about the behavior, said he first learned the younger Ebel was a suspect in the killing of Clements on Thursday.
His first reaction? "There can't be two Evan Ebels."
"I didn't even know Evan was out," Hickenlooper said, adding that he called the Ebel family a short time later.
The Ebels, according to Hickenlooper, were devastated by the news.
The governor said he never intervened on behalf of the younger Ebel, and he said Jack Ebel never made such a request.
Lengthy prison record
In 2003, at the age of 18, Evan Ebel was charged with felony armed robbery after brandishing a gun and threatening to kill a man unless he handed over his wallet, court documents show.
"I'm not playing. ... This is not a joke," Ebel said as he pointed a gun at the victim's head, according to witness statements at the time.
Ebel pleaded guilty to the charge and was sentenced to three years in prison, serving just over a year.
Just months after his release, he was arrested again. This time for felony menacing, robbery and assault. He pleaded guilty to those charges in 2005 and was sentenced to another three years in prison.
In 2006, while in prison, Ebel was charged with assaulting a detention officer, records show. He pleaded guilty and received an additional four years on his sentence.
Ebel spent five years of his sentence in solitary confinement, Hickenlooper said.