Investigators have said the gun Ebel used in the Texas shootout also was used to kill Clements.
Sheriff's investigators said they don't know the whereabouts of Lohr and Guolee or if they are together, but it's possible one or both of them could be headed to Nevada or Texas, Kramer said.
The 211 gang is one of the most vicious white supremacist groups operating in U.S. prisons, according to the Southern Poverty Law Center, which tracks extremist groups. The gang was founded in 1995 to protect white prisoners from attacks and operates only in Colorado, according to the center.
Guolee is a parolee who served time for intimidating a witness and giving a pawnbroker false information, among other charges, court records show. State corrections records show he served time for offenses in El Paso County before being paroled in southeastern Colorado.
His father, Phil Guolee of Wisconsin, told The Denver Post his son had been in prison since he was 18, is bipolar and wasn't able to have his medication in prison.
"He couldn't get any help, he couldn't get a good lawyer, couldn't get anything for him in Colorado," he said.
Lohr was being sought on warrants out of Las Animas County for bail and protection-order violations, according to court records.
He was arrested Dec. 1 in Trinidad while hanging out with friends at a tattoo shop because police said he was drinking in violation of the protection order. The name of the person being protected by the order was redacted from the documents. The court issued a warrant for Lohr's arrest after he failed to appear in that case Feb. 20.
Ebel was a model parolee for his first six weeks out of prison, according to corrections documents. But records show the vendor operating the electronic monitoring bracelet that Ebel wore noted a "tamper alert" March 14. Corrections officials left a message for Ebel telling him to report in two days and have the bracelet repaired, documents show.
The next day, for the first time since his release, Ebel did not call in for his daily phone check-in.
On March 16, he missed his appointment to repair the bracelet. Only on the following day do the records show that a note was made in the corrections system that he failed to show up.
By then, Nathan Leon, a father of three, was shot and killed after heading out to deliver a pizza to a Denver truck stop.
On March 18, parole officers contacted Ebel's father, who said he was concerned his son had left and gave them permission to search Ebel's apartment. The next afternoon, two parole officers concluded he had fled.
Hours later, Clements answered his doorbell and was fatally shot.
The next morning, still unaware of a connection with the most recent slaying, the state issued a warrant for Ebel's arrest on parole violations.
A sheriff's deputy in rural Texas pulled over Ebel on March 21, but he fled. Ebel was killed in a shootout that followed.
Clements, born in St. Louis, worked for 31 years in the Missouri Department of Corrections, both in prison and as a parole officer, before he joined the Colorado Department of Corrections in 2011.
His widow has asked that donations from state workers go to Leon's family, corrections officials said.
Associated Press writers P. Solomon Banda, Nicholas Riccardi and Alexandra Tilsley in Denver contributed to this report.