An ex-Alpharetta middle school teacher is in the Fulton County Jail after police say he secretly videotaped a teen relative as she got undressed in his home.

John Link Walsh, a teacher at Webb Bridge Middle School until he resigned Tuesday, was arrested Sunday on a charge of unlawful eavesdropping or surveillance, according to a police report obtained by The Atlanta Journal-Constitution.

According to the report, the teen was getting dressed Saturday when she found a black iPhone 6 hidden on a bookshelf. The phone’s camera faced her.

She picked up the iPhone and “the screen stated video recording finished,” police said. She told investigators she played the video, which showed Walsh allegedly setting up and covering the camera.

“She said the phone’s field of view captured her undressed,” police said in the report.

The teen panicked, deleted the video, dressed and left Walsh’s house with the iPhone. She called police from a friend’s house.

After interviewing the teen, confiscating the phone and tracking Walsh at his parents’ house, Alpharetta police made arrangements with Walsh to come to headquarters by 2 p.m. Sunday.

Walsh, 43, surrendered at the pre-arranged time, but refused to speak to police, according to the report.

He remained in the county jail Tuesday in lieu of $5,000 bond, Fulton County Sheriff’s Office spokeswoman Tracy Flanagan said. He is scheduled to appear in court on March 7.

Webb Bridge Middle School sent home letters alerting parents of Walsh’s arrest, Fulton schools spokeswoman Susan Hale told The AJC.

“Fulton County Schools is aware of the serious charges involving Mr. Walsh, who has resigned his position,” she said. “Our school system is fully cooperating with the Alpharetta Police Department in their investigation of this off-campus incident.”