A federal grand jury has formally indicted the son of a missing Easton couple.

Prosecutors say Kyle Navin is charged with possession of a firearm by an individual who is an unlawful user of and addicted to any controlled substance.

Police say they found guns and drugs, including prescription painkillers, traces of heroin and hypodermic needles, when they searched Navin's home in Bridgeport.

Navin was named a person of interest in the case of his missing parents, Jeffrey and Jeanette Navin. Police say family members reported the couple missing Aug. 4. State police say a truck belonging to the couple was located at a commuter lot off of Route 15 in Westport.

Police say there have been some inconsistencies with Navin's story of the last time he saw his parents. They say the 27-year-old was the last person to have any contact with them.

Police say records show the last time the couple's cellphones were in use was in or around Navin's home in Bridgeport. They say the times the phones were last active do not match the times Navin had provided of when he last had contact with his parents.

Police also say a texting exchange between Navin and his father show Jeffrey had asked his son if he had hurt his mother, to which Navin said, "No."

Police also say they found drugs and a receipt from Home Depot dated Aug. 5, showing that Navin had bought bleach, drain opener, stain remover and cleanup bags.

Navin has not been charged in the case of his missing parents.