Authorities may be closer to solving the five-week disappearance of the owners of a Westport refuse hauler with the arrest this week of their son on a federal weapons charge.

A federal court affidavit released following Kyle Navin’s arraignment Tuesday in Bridgeport shows the FBI, state and Easton police appear to be building a case linking the 27-year-old Bridgeport resident with the possible murder of his parents, Jeffrey and Jeanette Navin, the owners of J&J Refuse in Westport.

The younger Navin was formally charged with illegal possession of a firearm by an individual who is an unlawful user of, or addicted to, any controlled substance.

The charge is based on a search of Kyle Navin’s Bridgeport residence last month in connection with the ongoing investigation into his parents’ disappearance. Jeffrey Navin, the 56-year-old president of J&J Refuse, and his wife, Jeanette Navin, 55, a Weston Intermediate School library paraprofessional, have not been seen since Aug. 4. Former Westport and Weston residents, the senior Navins’ latest residence is in Easton.

A pickup truck belonging to the Navins — with one of its windows smashed — was found Aug. 9 in a Westport commuter parking lot off Exit 42 of the Merritt Parkway.

Among the evidence the FBI has, according to the affidavit, are texts between the father and son on the day the parents were last seen.

“I’m not going home till I know mom is okay,” Jeffrey Navin texted Kyle Navin at 12:39 p.m. Aug. 4. Three minutes later: “Did you hurt mom?” Jeffrey texted Kyle.

“No absolutely not. Why would you think?” Kyle Navin replied. “I go home and get framed for murder,” the father continued.

“Oh stop,” Kyle Navin replied. “I’m going to the police first,” Jeffrey Navin texted.

On Tuesday afternoon, Kyle Navin, dressed in bedroom slippers, red shorts and a black T-shirt advertising a local biker bar, limped into U.S. District Magistrate-Judge William Garfinkel’s courtroom in Bridgeport, escorted by U.S. Marshals.

His lawyer, Eugene Riccio, stood beside him as Navin answered, “Yes, your honor,” to each of the questions about understanding his constitutional rights asked by the judge.

The firearms charge Havin faces is punishable by up to 10 years in prison.

Riccio declined comment. The case was continued to Sept. 22.

The affidavit states that during a search of Navin’s house on Aldine Avenue in Bridgeport, Bridgeport police found a Smith & Wesson .380 handgun with a laser sight and a .40-cailber Sig Sauer handgun along with several boxes of ammunition. It states that State Police later found 15 hypodermic needles, dozens of glassine bags that appeared to contain heroin residue and two dozen empty Oxycodone prescription bottles at the house.

The affidavit also states that texts between Kyle Navin and his girlfriend discuss Navin’s use of heroin, Oxycodone and Xanax.

On Aug. 5 — the day after his parents were last seen — Kyle Navin purchased a germicidal bleach, hair/grease-dissolving drain opener and contractor cleanup bags from Home Depot, the affidavit states.

Kyle Navin worked at the family’s trash-collection company.

The affidavit states that Kyle Navin told investigators Aug. 11 that he had met his mother on the morning of Aug. 4 at the commuter lot off Exit 42 of the Merrit Parkway in Westport. He told police his mother got into his garbage truck and that they then went to collect garbage along his regular route. He said he later dropped off Jeanette Navin at the commuter lot, where she was met by Jeffrey Navin. He said he then went home.

Kyle Navin told police he later drove to his parents’ Easton home, where he picked up his paycheck, which his father had left taped to the door, and then went back home, the affidavit states.

But two days later, Navin told police a different story. This time, the affidavit states, Navin contended that he met both his parents at the commuter lot in the morning. His mother got into his garbage truck and Kyle Navin asked her if she could finish his route because his back was bothering him, the affidavit states. But she didn’t know the route and he ended up driving her back to Westport where they met up with Jeffrey Navin. Kyle Navin claims he then went home.

The last call Jeanette Navin made on her cell phone was at 8:45 a.m. Aug. 4, in the area of her son’s home. Her husband’s last cell phone call was at 1:23 p.m. that day, also in the area on Kyle Navin’s Bridgeport home.

Kyle Navin’s girlfriend later admitted that on the afternoon of Aug. 4, he had asked her to follow him as he drove his father’s truck to his parents’ Easton home. The girlfriend “could offer no reason as to why or how Jeffrey’s truck came to be in Bridgeport or why Navin needed to drive the truck back to Easton,” the affidavit states.