She used to sing and dance at local programmes, and had earned a reputation as a good performer in the neighbourhood in her home district Khulna.

But things started to change around three to four years ago.

The girl, Ishtishna Akhter Oishee, had stopped attending cultural programmes since then, and there was an apparent shift in her behaviour, say locals and relatives at her ancestral home in Mikshimill village.

Oishee, an intern at Dhaka Medical College Hospital, was arrested by Rab from the capital's Moghbazar along with three other suspected female operatives of banned militant outfit Jama'atul Mujahideen Bangladesh on Tuesday.

Influenced by a friend abroad, the 25-year-old girl got involved in militancy around four years back, according to Rab. 

She comes from a well-off family. Her father Dr Biswas Akhter Hossain is an associate professor at chest diseases department of the DMCH. Her mother Nasima Rahman is also a physician.

One of her paternal uncles is a deputy inspector general of police and another is a physician in the capital, reports a correspondent from Khulna.

Abdul Mannan, one of Oishee's neighbours in her village under Dumuria upazila, said he couldn't believe that she got involved in militancy.

“She is a doctor. She used to perform at cultural events. How could she become a militant?” asked a surprised Mannan.

Saidur Rahman Piaru, ex-union parishad member of Udhagara union where Oishee is from, said they noticed a change in her behaviour three to four years back.

She stopped taking part in cultural functions and started wearing burka and hijab, he said.

Talking to The Daily Star over the phone yesterday, Oishee's father Dr Biswas said his daughter always followed religious dictates and donated money to the needy.

But they could not even imagine that she would get involved in militancy, he added.

According to Rab, Oishee has been involved in militancy for around four years. Inspired by one of her friends abroad, she joined a militant network using “codename Marfat” on Facebook around four years back.

Later, she joined the JMB through a friend in Dhaka.

To maintain a secure communication and avoid detection by law enforcement agencies, she used Telegram and Threema apps, Rab said.

Oishee joined different Facebook groups that support militancy. She shared provocative photographs and video clips of militant activities to inspire people to join militancy, said the elite force.

Seeking anonymity, a Rab official said Aklima Rahman Moni, a pharmacy student at Manarat International University in the capital, encouraged Oishee to join the JMB.

Aklima, arrested along with Oishee and two others on Tuesday, was given the responsibility by JMB leader Mahmudul Hasan for forming a female JMB unit.

Rab arrested Mahmudul, JMB ameer of the southern region, from Gazipur on July 21.

“Oishee used to attend group discussions in Dhanmondi area where she met Aklima around a year ago. Aklima convinced her that they needed an organisation to propagate their ideology. Oishee was then recruited by the JMB,” he added.

She got more active in militant activities and eventually became an important member of the female JMB unit. Oishee and Aklima used to take crucial decisions for the unit, said Rab officials quoting the four arrestees. 

The two other arrestees are Khadija Parveen Meghla and Ishrat Jahan Mou.

The four were allegedly spreading extremist ideologies among young women in the name of teaching Arabic language. Their initial objective was to strengthen the female unit and collect funds for terror activities, added the Rab officials.