A 22-year-old girl has been arrested from Hajipur in Vaishali district for allegedly kidnapping a minor girl for marriage in the first case of its kind in at least the last four years in Bihar.

Both the girls, however, claimed they had eloped and got married. While the older girl worked with a private firm in Patna, the younger one, who is 17, took the matriculation examination this year.

Vaishali superintendent of police (SP) Rakesh Kumar said the minor girl was produced before the court of the Hajipur judicial magistrate on Tuesday to record her statement under section 164 of the CrPC.

She was also sent to the Hajipur sadar hospital for medical examination, he added.

Both the girls were taken into custody from Ramashish Chowk after they returned to Hajipur, around 20km north of Patna, from Mumbai by train on Monday evening.

The older girl was arrested and forwarded to jail on the charge of kidnapping the minor girl.

"As the younger girl is below 18 years of age, she was sent to a remand home on the order of the court. Earlier, the parents of both the girls had lodged kidnapping cases separately with the Bidupur police station of the district," the SP told The Telegraph over phone on Tuesday.

The girls are learnt to have told the police that they were living as husband and wife for the past one year, and on April 10 this year they had gone to Mumbai to inquire about gender change surgery.

The older girl said she had saved up Rs 45,000 from her salary for the trip.

"Though we informed our parents about our relationship a year ago, they didn't allow us to live together. Finally we decided to elope," an officer posted at the Bidupur police station quoted the girls as saying.

The girls repeatedly requested senior police officers to persuade their parents to accept their "marriage".

The older girl said she first met the younger girl at a wedding ceremony.

Their friendship turned later into a relationship, she told her interrogators at the Bidupur police station, where she was detained.

Bidupur police station house officer Lallan Choudhary said the parents of both the girls have been informed about the developments in the case.

The older girl's father is a government employee in Samastipur district.

The minor girl, police sources said, has threatened to commit suicide if she is separated from her "husband".