Police say that a high speed chase, that ended in the death of the driver and a wounded sheriff's deputy, may be tied to the shooting of Colorado prison chief Tom Clements. 
Authorities in northern Texas tried to pull over a man driving a black Cadillac, triggering the shootout and crash. Authorities say the car is the key link to Clements' killing. 
Firemen and emergency workers carry the suspect to a waiting ambulance. The suspect, identified as Evan Ebel, later died. 
Evan Ebel was former Colorado prison inmate and a former member of a white supremacist group. 
Pictured is the house where Tom Clements, head of Colorado state's prison system, was shot and killed in Monument, Colorado, on March 20, 2013. 
The Colorado Department of Corrections Executive Director Tom Clements was shot dead as he arrived home Tuesday evening, March 19, 2013. - An affidavit says a pizza box and uniform were found in the Cadillac
- Authorities are working to link Evan Ebel, 28, to the killing of Colorado's prison chief
- Investigators are also looking at Ebel for the death of pizza delivery man
- Ebel died Thursday after following a shootout with Texas authorities
Colorado Springs, Colorado (CNN) -- A black Cadillac, bullet casings and a pizza box appear to connect a parolee with ties to a white supremacist prison gang to the shooting death of Colorado's prisons chief, according to a search warrant affidavit obtained Friday by CNN.
The affidavit, filed by the Texas Department of Public Safety's Ranger Division, details what authorities believe links Evan Spencer Ebel, who died in a shootout with sheriff's deputies in Texas, and the Colorado killing of state prisons chief Tom Clement.
Of key focus in the affidavit is a 1991 black Cadillac that authorities say Ebel was driving in a wild, high-speed chase Thursday that saw the 28-year-old open fire on sheriff's deputies before slamming into an 18-wheeler, climbing out of the wreckage and opening fire again.
Hours later, Ebel died from a gunshot wound to head suffered during the shootout, leaving behind more questions than answers in a case that has spanned two states.
On Friday, the wreckage of the Cadillac was under intense scrutiny after witnesses reported a similar vehicle -- a black, boxy car with Colorado license plates -- near the Monument, Colorado, house of Clements on Tuesday, the day he was killed.
Among the links in the cases, according to the affidavit, are shell casings from a .9mm handgun found at Clements house. They are the same brand and caliber used in the shooting of a Wise County, Texas, sheriff's deputy, it said.
Video: Pizza deliveryman remembered
In the Cadillac's trunk was a Domino's Pizza box carrier and a Dominos uniform jacket, it said.
That pizza carrier and jacket are a key reason why Denver authorities are also in Texas to examine the Cadillac.
They are investigating the killing of 27-year-old Nathan Collin Leon, a Domino's Pizza delivery worker in Denver.
Leon disappeared from work on Sunday and was found dead in the Denver suburb of Golden. Leon's family said he delivered pizzas as a way to earn extra money for his wife and his three girls.
Denver investigators tell CNN there is a "strong connection" between the killings of Leon and Clements.
Even as the investigation appears to link Ebel to the shooting, authorities have said little about a possible motive.
Did Ebel kill a pizza delivery man to get a hold of his uniform as part of an effort to disguise himself? Did he target Clements because of the prison chief's crackdown on white supremacist gangs in prison? Was he part of a wider conspiracy to kill Clements? Or was it something else?
High-speed chase in Texas
This much is known: On Thursday, Ebel sped through Montague County, Texas, near the Oklahoma state line, about 700 miles from Monument.
Deputy James Boyd tried to pull the car over. It's unclear exactly why, other than it would have a been a routine part of Boyd's job.
Boyd did not know about the Clements case, authorities said.
Ebel shot the deputy three times, hitting him twice in the chest and grazing his head. Wearing a bulletproof vest, the deputy managed to call for help and to tell law enforcement which way Ebel was driving. Authorities say they have looked at the dashcam video of the shooting.
Boyd remains hospitalized at a Dallas-Fort Worth area hospital.
The information the deputy gave allowed law enforcement to catch up with Ebel.
A high-speed chase ensued, ending about 30 miles away in Decatur, Texas, with Ebel firing out of his window at police, law enforcement said.
"I would say he was running about 100 mph, and he had his left arm out the window and he was just shooting," said Decatur Police Chief Rex Hoskins, whose patrol car was parked in the median as the Cadillac raced past.
The chase ended when the Cadillac screeched onto another road and slammed into an 18-wheel truck, authorities said. With the front of his car crushed, Ebel got out and started shooting again.
Ebel didn't hit any officers this time, they said. But they shot him.
He was taken to an area hospital where he was pronounced dead Thursday night, authorities said.
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.
Ebel has a lengthy criminal history, according Sheriff David Walker of Wise County, Texas.
Records show that in 2005 Ebel was convicted of felony menacing, assault and robbery. In 2006, Ebel pleaded guilty to assaulting a detention officer, records show.
The emerging details about the investigation appear to indicate authorities are shifting away from considering the possible involvement of Homaidan al-Turki, a Saudi national.
On Thursday, Presley said that investigators were considering the possible involvement of al-Turki after a local news outlet, citing an anonymous source, said they were looking at connections between the Saudi national and Clement.
Al-Turki was convicted of sexually assaulting his housemaid at his Aurora, Colorado, home seven years ago. This month, Clements denied al-Turki's request to serve the remainder of his Colorado prison sentence in Saudi Arabia, records show.
Attorneys for al-Turki did not immediately return a CNN request for comment.
Read the latest news on CNN.com
CNN's Jim Spellman reported from Colorado and Ed Lavandera from Texas, and Chelsea J. Carter reported and wrote from Atlanta. CNN's Ashley Fantz and Drew Griffin contributed to this report.
