Mukherjee was asked to be present at the CBI office in Salt Lake, on the northern outskirts of Kolkata, before 11 am. m. on Thursday. Md Salim, party politburo member and state secretary in West Bengal, said Mukherjee, who is now out of the station, will reach the city only on Thursday morning and from the station he will go directly to the CBI office.

After the victim's body was recovered from the hospital's seminar room on the morning of August 9, Mukherjee rushed to the hospital and was one of the few who interacted with the victim's parents that day.

The CPI(M) leadership had claimed several times that it was it who resisted the city police's attempts to immediately cremate the victim's body.

It is learned that a few days ago Mukherjee received a call from a number where a person who identified himself as a CBI officer asked him to be present at CBI's Salt Lake to be questioned as a witness in the rape and murder case.

Later, the CPI(M) leadership verified the credentials of the caller and ascertained that she was a member of the CBI team probing the rape-murder case.

Sources said Mukherjee was also at a protest site near R.G. Kar at midnight on August 14, when a group of antisocial elements destroyed the emergency service of the R.G. Kar.

The vandalism took place at a time when thousands of people were on the streets in different areas of the state as part of 'Meyera Raat Dakhal Koro (women, reclaim the night)' protesting against the macabre tragedy.

The state government and the Kolkata police came under huge criticism following the incident. While some claimed that the attack was carried out deliberately to divert attention from the protest programme, others claimed that it was an attempt to destroy evidence at the crime scene within the hospital premises.

Sources said Mukherjee may also be questioned by CBI sleuths about her experience that night.