Officials said Wednesday the gun was recovered when Even Ebel, 22, was shot and killed by Texas law enforcement officials following a high-speed chase and exchange of gunfire March 21, The Denver Post reported Thursday.
Clements, 58, was killed March 19 when he opened the front door at his home in Monument.
Stevie Marie Vigil, 22, of Commerce City, was arrested Wednesday on charges she bought the gun from a licensed firearms dealer and gave it to Ebel, who would have been barred from buying a gun because he was a felon, the Post said.
"The licensed firearms dealer has been extremely cooperative with investigators, and had no knowledge of Vigil's alleged actions following her legal purchase of the gun," the bureau said Wednesday in a release.
Ebel also was linked to the death of 27-year-old pizza delivery man Nathan Leon, who was reported missing after going on a delivery March 17, two days before Clements was fatally shot.
Police have said ballistics tie the 9 mm Smith & Wesson pistol recovered by Texas officials to Clements' death but have not determined whether the same gun was used in the Leon shooting.