Farooqui was arrested on Friday in Bhopal and brought to Indore on Saturday afternoon by a CBI special crime branch team.
The CBI spokesperson had said in New Delhi that she is understood to be aware of the crime and believed to have assisted in the conspiracy.
Farooqui was an employee of Parvez for last five to six months and had developed close friendship with her, CBI sources said. They said she knew Parvez's relations with a Bharatiya Janata Party MLA and was also aware about her growing resentment towards Masood, also believed to be close to the politician.
From the personal diary of 36-year-old Parvez, recovered by the agency on Thursday during its searches at her residence, the CBI has found some entries which show close proximity of Farooqui with the architect, they said.
One such entry shows that both had celebrated on the evening Masood was murdered, the sources said.
Masood was shot dead outside her house at Koh-e-Fiza locality on August 16 last year when she was going to take part in protests in support of Jan Lokpal Bill.
An RTI activist, Masood had worked in several areas including environment protection, conservation of wildlife and anti-corruption movement.