Published: May 30, 2013 10:16 AM EDT
Updated: May 30, 2013 12:42 PM EDT

COLLIER COUNTY, Fla.- A Collier County man and his mother, both accused of health care fraud, entered pleas of "not guilty" before a federal judge Thursday morning.
Delmer and Patricia Parrish worked at Sunshine Pharmacy in Naples. They were arrested in a nationwide health care fraud sting earlier this month. Since then, both have been out of jail on bond.

Federal investigators say the mother and son used their pharmacy to defraud Medicare, Medicaid, and TRICARE over the period of three years.

According to authorities, they billed for prescriptions that were never filled and submitted claims for deceased patients.

Both face up to 10 years in federal prison if convicted.