The police have cracked the murder case of an IAS officer's advocate daughter with the arrest of the watchman of the building where she lived in central Mumbai.

"Watchman Sajid Mugal was arrested on Thursday night for the murder and he has confessed to the crime," a crime branch official said on Friday.

Pallavi Purkayastha (25) was found in a pool of blood on Thursday morning at her rented flat in 'Himalayan Heights' building at Wadala by her live-in partner Avik Sengupta (26), also a lawyer.

Pallavi, the daughter of IAS officer Atanu Purkayastha, who is posted as joint secretary in Ministry of Agriculture in New Delhi, was working as a legal advisor with filmmaker Farhan Akhtar's firm Excel Entertainment Pvt Ltd.

Police said Mugal deliberately cut-off the power supply to Pallavi's flat sometime before the murder, following which she had to call electricians and get it restored.

He had also tried to molest her a few weeks ago, police said, but refused to elaborate the sequence of events and the motive behind the gruesome murder.

"Pallavi's body has multiple stab injuries. The scene of crime indicates she struggled to save herself. When Avik returned home, he found that the door was slightly opened...he went inside and found the blood-soaked body of Pallavi with the throat slit, following which he informed the police," he said.