A joint investigation involving Yorktown police, county police and the Federal Bureau of Alcohol, Tobacco and Firearms (ATF) resulted in a Peekskill man heading to prison on federal firearms charges.

Christopher Hammonds, 25, pleaded guilty this week after he was caught selling guns to investigators. According to police, when Hammonds was arrested in September he was also trying to sell them crack cocaine. State drug charges against him are still pending. Hammonds is being held without bail until his sentencing on January 31.

Investigators say the key to the case was close cooperation between town police, county police and federal ATF agents. All three agencies say that cooperation will continue.