FORT COLLINS, Colo.?An Air Force airman was arrested Tuesday for a string of sexual assaults in this college town last summer and has also come under suspicion in a slaying and a series of rapes in Philadelphia.

Airman 1st Class Troy Graves, 29, was jailed on $1 million bail.

In the Fort Collins attacks, an intruder entered apartments through unlocked doors or windows in the early morning, blindfolded his victims and forced them to perform a sex act. All six assaults involved women in their 20s living in apartments near the Colorado State Campus.

Fort Collins police said DNA evidence connected the same man to all six attacks.

Graves is also a suspect for sexual assaults in the well-to do Rittenhouse Square neighborhood from 1997 to 1999. Police connected six Philadelphia crimes?including the strangling of University of Pennsylvania student Shannon Schieber?to Graves through DNA matches.