Her arrest stemmed from the "oldest outstanding murder warrant obtained by the Denver Police Department," said Avendano.
Avendano said she didn't know if Lester had an attorney. She had been living in Dayton under the name Agnes Ramey.
According to a Denver Post article from the time, Schlatter was playing pool at the Blue Chip Bar on Nov. 8, 1968, when he and Lester got into a scuffle. Lester, a Denver resident, allegedly pulled out a .22-caliber gun and shot Schlatter in the chest.
Witnesses told police Schlatter grabbed the gun and fired three shots at Lester as she fled. Schlatter then collapsed and died.
Avendano said "good police work" and the use of new technologies led to Lester's arrest.
"A determined police officer followed up on the case and was able to find her," she said. "How that was, I don't know exactly."
Denver police were headed to Dayton to question Lester and possibly transport her back to Colorado, Jim Wahlrad of the U.S. Marshals Service told the Dayton Daily News.