A distraught mother was arrested and handcuffed by police as she tried to stop her teenage son leaving with a "sinister" religious cult she believed brainwashed him.

Now there are fears that the cult, known as the Jesus Christians, which is said to order converts to reject their families, may be targeting student campuses.

Bernadette Sheridan reported 19-year-old Kyri missing after he told her he was going travelling with "missionaries". He had been due to return home to London last weekend after his first year at Surrey University in Guildford. But in a space of a few days friends noticed he changed from happy-go-lucky and energetic into a sunken-cheeked, exhausted and manic young man with staring eyes.

Worried by his odd behaviour, they began quizzing him about his movements but the popular teenager; who neither drank nor smoked, became evasive.

He had been given literature by a man he knew as Francisco and told his mother that the group had asked him to go North with them for a few days to see the work they do.

He promised to call Miss Sheridan, a religious education teacher, but never did. In a comic book called Liberator produced by the Jesus Christians, Miss Sheridan found a mobile phone number for the group and talked to a woman called Sue. She was chilled to hear the woman tell her: "He's ours now. We can offer him the love and support of a mother."

Unable to contact Kyri, Miss Sheridan called police. Officers at Guildford also called the number and Kyri called back. He was told he would have to report to the police station to have his name removed from the missing person's list.

When he appeared, accompanied by Francisco, Mis Sheridan, one of his friends, and two other members of his family were waiting. "He looked like a zombie," his friend recalled. "His eyes were glazed and he was breathing strangely. It was really scary. His mum was hugging him and saying 'I love you, wake up, come back to us' but the guy from the group stared at her and said 'He's not your son any more, your job is finished, he's ours now'"

Desperate not to let her son go, Miss Sheridan clung to him in the street until Francisco called the police on his mobile phone.

In the scuffle, Miss Sheridan was pulled off Kyri and arrested. She could only watch as her son was led to a waiting van which drove away. She has not seen or heard from him since. "I was arrested for hugging my son." Miss Sheridan said last night. "I love Kyri and I'm worried about his welfare. I want to speak to him and I want to know where he is."

Founded by an Australian called David Mckay, the Jesus Christians are intensely secretive and no one knows where their headquarters are. Graham Baldwin, of Catalyst, a charity set up to help the families of people caught up in cults, said: "They are very sinister."