Man arrested for alleged kidnapping on houseboat at Lake Powell

KANE COUNTY, Utah (ABC4) — A man staying in a houseboat on Lake Powell was arrested after allegedly refusing to let guests and family members leave when he made them feel unsafe, documents say.

Steven Thornley is facing four charges of kidnapping, a second-degree felony; one count of domestic violence in the presence of a child, a Class B misdemeanor; damaging/interrupting a communication device, a Class B misdemeanor and disorderly conduct, an infraction.

According to documents, on July 2, 2025, several 911 calls were placed to Kane County and Glen Canyon dispatch regarding a domestic violence situation on a houseboat near Gunsight Point on Lake Powell. Reports from callers “indicated that several individuals were attempting to leave the houseboat,” but that the suspect was not allowing them to.

National Park Service (NPS) Rangers told the Kane County Sheriff’s Office that they would respond to the scene by boat. Rangers were able to make phone contact with individuals on the boat, who informed them that there were roughly 12 people on the houseboat. They also said that two firearms were there, but had been hidden from the suspect.

The suspect, later identified as Thornley, then began speaking with rangers over the phone. Thornley told the rangers that he was preventing people aboard from leaving because he did not recognize who had come to pick them up.

Documents say Thornley asked the rangers to “verify the registration, insurance, and captain’s license” from the other boat. Rangers told Thornley that they could not do that, and that if people wanted to leave the houseboat, he needed to let them.

Thornley allegedly replied that he understood, but told police that his immediate family members aboard were “his property and they would not be leaving.” Rangers again told Thornley that anyone who wanted to leave if they felt unsafe should be allowed to.

Rangers asked to speak with one of the suspect’s family members. When they made contact with the family member over the phone, “an apparent altercation occurred” and “yelling was heard” before the call was disconnected. Witnesses later told police that Thornley had “violently grabbed [the family member] by the neck and shoulders in an attempt to take the phone.”

Phone contact was made again, and rangers were told that everyone on the boat had been allowed to leave except three immediate family members and a family friend of Thornley. NPS rangers responded to the houseboat and removed the four individuals. Thornley was located “lying face down in the living room with his hands visible and extended,” documents say.

After being safely removed, police interviewed witnesses about what happened on the houseboat. The people who were onboard “reported feeling threatened, afraid and unsafe” due to Thornley’s behavior, according to the arrest statement.

The situation reportedly began when Thornely “repeatedly yelled at everyone on board, declared himself the captain, and said, ‘If you don’t like it, get off the boat.'”

The individuals on the houseboat contacted a friend to help them get off the houseboat, but when that friend arrived, Thornley allegedly became hostile. Witnesses told police that he threatened to sue anyone who left. Those who wanted to leave had to jump off the houseboat and swim to their friend’s boat.

When the four remaining individuals expressed wanting to leave, Thornley “physically blocked the exit path, stood in the way,” and even moved objects to block them from leaving. After they were the only ones remaining on the boat, Thornley reportedly went to “an unknown location” and did not return until rangers arrived.

Thornley was taken into custody and booked into the Kane County Jail. He is currently being held without bail.