A 53-year-old man has pleaded not guilty to charges that he caused another man's death by putting methamphetamine in his drink.

Jon Freiberg of Casper pleaded not guilty Wednesday in District Court to one felony charge of involuntary manslaughter. He also pleaded not guilty to various other felony charges related to possession and delivery of a controlled substance.

Court documents say 46-year-old Richard Serafin died last August after Freiberg put meth in a cup Serafin was drinking from. The documents indicate Serafin consumed the drugs accidentally.

An autopsy report says Serafin died of cardiac arrest due to the stress of meth intoxication and other health issues.

Freiberg is being held in the Natrona County Detention Center.