A former Island resident and licensed therapist has pleaded not guilty to accusations of misconduct after being caught unclothed with a 15-year-old boy at his home earlier this year.

According to documents released by the King County Prosecutor’s office, Thomas Arthur Gill, 63, a recent resident of Mercer Island, has been charged with one count each of indecent liberties and communication with a minor for immoral purposes. Gill was arraigned last week and pleaded not guilty. His attorney said all charges would be contested in court. Gill’s social worker license was also recently suspended from the state Board of Health. The defendant is out of jail on $15,000 bail. Gill sold his family’s Island home where the majority of the misconduct is suspected to have taken place two days before the incident occurred, county property records show.

The victim, who was diagnosed with autism, is a resident of Shoreline, but Gill was the boy’s therapist and had occasionally counseled the teenager at his former Island home that is located near the high school. Gill was counseling the victim through the Attachment Center Northwest in Kirkland, a firm specializing in treating youth with attachment and trauma-related issues.

According to an investigation led by Island police detective Art Munoz, the defendant’s son had gone to see his father at the Island home on Saturday, May 10, went to his father’s bedroom and discovered his dad completely nude reaching for a night gown. The son also saw the victim run across the room toward the bathroom without any clothes on, according to court documents. Police and Child Protective Services were notified of the incident after the victim mentioned it to an educator in his Shoreline Crest High School classroom. During interviews with Munoz, the victim told police he had also been unclothed and discussed sex during numerous therapy sessions at Gill’s former Mercer Island home. Inappropriate touching that occurred at Gill’s home was documented in the investigation as well.

According to Munoz’s investigation, Gill’s son confronted his father about what he saw take place in his bedroom.

“[The son] stated that he spoke to his father later in the night about what he saw and that his father told him they were just each taking a shower one after the other and he caught them between that time,” Munoz wrote in his investigation. The son also told Munoz that he told his dad he thought more was going on, but his father denied anything else had happened.

Munoz also interviewed the victim’s mother, who told the detective that her son had been seeing Gill weekly for therapy for three years. She was notified of the incident by another doctor treating her son.

Court documents reveal there are other potential victims that need to be identified and interviewed. Munoz said there were no new leads or victims identified at this point, but the investigation was ongoing. A case-setting court hearing will take place on July 10.