In a major breakthrough in the Shehla Masood murder case, the Central Bureau of Investigation (CBI) has arrested a woman interior designer for alleged  involvement in the murder of the activist in Bhopal last August, said an agency official Tuesday.

Along with the woman, identified as Zahida Pervez, another person, whom Pervez had allegedly hired to kill Masood, was arrested Tuesday from Bhopal. 

"Pervez is at present in CBI custody and it is believed that she had some personal rivalry with the RTI activist," said the official. 

Pervez, whom the CBI had earlier identified as an architect, had reportedly told the CBI investigators that she had had developed a deep, personal enmity with Masood and hired a contract killer to eliminate her.

According to sources, the murder was an outcome of a extra-marital affair. The sources claimed that they have confessional statement from Pervez, the wife of Asad Parvez, a petrol pump owner. Her father-in-law Mullah Sajjad Husain alias Fakru Bhai is a prominent citizen of the city.

According to a statement from the CBI, the arrested duo will be brought before the designated court at Bhopal Wednesday.

The 32-year-old Masood was shot dead in broad daylight in front of her house. The CBI had taken over the case three weeks after the murder.

The Bhopal unit of the CBI was looking into the murder since the first week of September and even announced a reward of Rs.5 lakh for anyone giving information leading to the arrest of the assailants. 

However, as it failed to make any headway in the matter, the probe was handed over to the Delhi team of the CBI.

A CBI team from Delhi, comprising Joint Director Keshav and Deputy Inspector General (DIG) Arun Bosra, arrived in Bhopal Monday to take over the investigations.