A series of suspicious text messages were allegedly sent on the day Connecticut couple Jeffrey and Jeanette Navin disappeared, court documents reveal.At the same time, Kyle Navin, 27, the couple's son, was charged with possession of a firearm by an individual who is an unlawful user of, or addicted to, a controlled substance, authorities said. The investigation into the disappearance of his parents is ongoing. Kyle Navin has not been accused in his parents' disappearance.The husband and wife were last seen on Aug. 4, in Easton, Connecticut, and their truck was found abandoned by the side of a highway five days later.Court documents released by the U.S. Attorney's Office for the District of Connecticut allege that Kyle Navin and his father exchanged a series of text messages on Aug. 4. According to the documents, Jeffrey Navin texted his son, "I'm not going home till I know mom is okay" and "Did you hurt mom?""No absolutely not. Why would you think," the son responded, according to authorities."I go home and get framed for murder," the father wrote."Oh stop," Kyle Navin wrote.A few minutes later, according to the court documents, Jeffrey Navin responded, "U R setting me up."After the text messages were discovered, authorities said, Kyle Navin's home was raided, at which point two firearms, multiple rounds of ammunition and various drug paraphernalia were seized.The son also shopped at Home Depot the day after his parents went missing, according to the court documents -- purchasing bleach, stain remover and cleanup bags, authorities said. He also wrote a note that stated: "No alarms, no panic buttons, no phones. BE SMART," according to the criminal complaint.Kyle Navin has not yet entered a plea on his firemarm and controlled substance charges. He will be back in federal court Friday.