The murder of RTI activist Shehla Masood appears to be a "crime of passion" and whether it was part of any larger conspiracy is still a matter of investigation, CBI officials said on Tuesday.

"Investigations so far indicate the RTI activist's murder appears to be a crime of passion. Whether or not the murder was part of a larger conspiracy is a matter of further probe," the officials said here.

Specifically asked about the suspected role of Madhya Pradesh BJP MLA Dhruv Narayan Singh in the case, they said, "We have not given a clean chit to him."

The CBI has so far arrested three persons in connection with the case and they include city-based interior designer Zahida Pervez, her assistant Saba Farooqi and Shakib Ali 'Danger', an alleged history-sheeter.

Another suspect Irfaan was arrested by the Special Task Force of Uttar Pradesh Police at Kanpur for another case.

"So far, it is clear that interior designer Zahida Pervez was the one who gave the contract for eliminating Shehla to Shakib Danger," the officials alleged.

According to preliminary probe, Zahida was jealous of Masood's alleged closeness with MLA Singh.

A CBI team with the support of local police had closely examined nearly nine lakh calls especially those made from Koh-e-Fiza, the area where Masood lived and where she was shot dead on August 16 last year.

The monitoring of calls found that Masood was shot dead at 11:19:30-40. At 11.26 am, a confirmation call was made to Zahida, the officials claimed.

It was Shakib 'Danger' who had allegedly arranged for killers from Kanpur on the instructions of Zahida and a deal involving Rs 5 lakh was struck. Of this amount, Rs 3 lakh was paid to the assailants, the officials alleged.

Though the details of the entire crime was revealed by the alleged shooter, Irfaan, CBI is still in the process of stitching together the entire episode. The Central agency was also looking out for another shooter involved in the crime.

A court in Kanpur has allowed CBI to interrogate Irfaan in Bhopal. Meanwhile, CBI Director A P Singh, arrived here last night to review the progress in the high-profile murder case.