Texas couple allegedly kept adopted son, 22, in locked apt.

Jenifer and Dane Thyssen allegedly locked their 22-year-old adopted son in an apartment above the garage of their Dripping Springs, Texas, home.

CBS affiliate KEYE

DRIPPING SPRINGS, Texas - Central Texas police say a couple kept their adopted son locked in a garage apartment in an Austin suburb for at least four years, periodically giving him a box of food and allowing him to leave once a week.

Jenifer Elise Thyssen, 40, and Dane Andrew Thysse, 39, told police 22-year-old Koystya Thyssen was locked in the apartment to protect their other children. What the children allegedly needed protection from has not been revealed.

A police affidavit reveals the apartment behind the Dripping Springs home of was locked from the outside.

"[Jenifer and Dane] did everything they could and just ran out of options," defense attorney Perry Minton told CBS affiliate KEYE. "[Koystya] was allowed out. What they wouldn't do was just take off and let him roam around wherever and go out of the house."

According to an arrest affidavit obtained by the station, the garage "windows were all boarded up and the entry door was secured with a latch which was locked from the outside."

"[Koystya's] family has structured a situation and said you stay in here and we're going to integrate you in the family some, we're going to take you to counseling," said Minton. Counseling was reportedly the one day of the week where the 22-year-old could leave the garage and shower, according to KEYE.

Police began investigating when Koystya Thyssen was arrested for allegedly burglarizing a neighbor's home. Authorities say he used a screwdriver taken from his father to escape the apartment.

Minton believes the community should be concerned with what Koystya will do now that his parents are behind bars. "He will be out in the community with no one looking out for him and no one making sure he's not preying on others," he told the station.

Dane and Jenifer Thyssen were being held Friday at the Hays County jail on a kidnapping charge. Their adopted son also is being held there, on a burglary charge.