It depends on the talkgroup you heard them on. If it was a Denver Metro talkgroup, then someone might have dragged the talkgroup into the area (against best practices) and you were hearing operations in the Denver Metro area. Air1 almost always stays in the Denver Metro area unless there is an mutual aid request from another agency for exceptional circumstances. It is unlikely to leave the Denver Metro area for surveillance.
If you are sure that you heard them operating in Colorado Springs, then it is possible that it could have been a federal asset.
Some recent media covering Air1:
Denver Police Air Support Unit’s team of just three officers combine years of policing experience and expert flying to provide vital air cover to their colleagues on the ground.
verticalmag.com
I think Air1 is up in the evenings Tuesday through Saturday. Flight tracking is not very reliable for Air1 as they operate under the law enforcement ADS-B exemption allowing them to disable it when being used for law enforcement. The only time their ADS-B is on is when it is performing a maintenance flight to/from/at Century Helicopters, Inc. in Fort Collins.