Two years ago, Surya Lama decided to send his daughter Nisha away to a circus in India. The middleman promised she would earn IRs 100 a day and go to school.

Today, Nisha is among 30 Nepali girls who disappeared from The Great Roman Circus at Karnelganj near Lucknow, and Surya is in custody with three other parents at the Gonda police station. One of the circus girls who managed to escape, 14-year-old Nita Lama, is also in police detention.

Inside the police station in Gonda on Thursday, Nita caught me by the hand and wouldn't let me go. "Take me home with you, take me back to Nepal," she wept. Nita's mother, Thulimaya, is in shock and can't speak.

While the Nepali parents are in custody, the circus owner, Fateh Khan and his son Reza Khan drive around Lucknow openly carrying firearms and have threatened Nisha and the Nepalis inside the station.

The parents of the girls approached the Nepal Child Welfare Society (NCWS) in Butwal, which had rescued 29 Nepali boys and girls from a circus in Kerala in April. The society asked Indian child rights activist Kailash Satyarthi of the Bachpan Bachao Andolan for help.

When police raided the circus to rescue the girls on 15 June, it was clear the owner had been tipped off. Goons with iron rods started beating up the activists and parents. Reza Khan brandished a pistol in full view of tv cameras. The police just stood by while the girls were bundled away. Except Nisha, none have been seen since.

Two other parents, Bishnu-kumari and Janak Lama are on hunger strike at the state assembly in Lucknow, demanding to be reunited with their daughters. Satyarthi, who got a knife wound in his head, has abandoned his hunger strike because of threats.

The District Court in Gonda has ruled that Nisha's parents can take her away only after paying a IRs 50,000 bond. Says Khem Thapa of the NCWS: "Parents are being forced to buy back their own daughters."

On Sunday, Uttar Pradesh Labour Minister Kaushal Kishore told us: "I'm on the case, I'll allow the girls to go back with their guardians and I'll get circus licenses revoked." It doesn't look like these instructions have been passed down to the police in Gonda.

In the few minutes some of the parents got to see their daughters during the raid last week, the girls related horrifying tales of sexual exploitation, rape and beatings. Testimonies reveal the circus also operated a paedophile ring. The girls were forced to service policemen and state officials.

"The circus has full protection of the police and the state machinery," Kailash Satyarthi told us. He estimates there are 1,500 Nepali minors and teenagers working in circuses in India, where many are virtual sex slaves.

At the police station, Surya Lama is full of remorse for what he made his daughter go through. "It is all my fault, I am a sinner," he says breaking down. "I'm never going to let anyone else in my village make the same mistake I did."