He has been identified as one Alimiya Umar Chaus, 19, who had helped the prime accused, Aaradhya Patil alias Riya, 19, and her 16-year old (minor) boyfriend in the crime committed early morning of November 27.
The duo reportedly photographed and filmed the entire grisly act, ostensibly to share with friends later, as per the accused's statement, while Chaus helped them to pack up the victim's body parts.
That evening (November 27), Riya and her boyfriend went to meet Chaus in Ghatkopar to procure a chopper to cut Rebello's body into pieces, but he refused to cooperate.
After two days, they again met Chaus in Vidyavihar and sought his help to dispose off the body which they had chopped into eight pieces, to which he apparently agreed, said police.
While Riya and the minor boy were stuffing the suitcase and two plastic bags with Rebello's body pieces late that night, Chaus allegedly assisted them by providing gum tapes to seal the bags.
The trio also went out to a local shop to arrange for other packing material to stuff the torso, and later Chaus spent the night at the victim's flat in Kalina, Santacruz east, the scene of the ghastly murder.
The development came a day after the police recovered the 59-year old Rebello's head and torso from the Arabian Sea off Shivaji Park and his visual identification by his brother, Jude Rebello.
Forensic experts have concluded that the victim had fought his killers and found head injuries, contusions and multiple stabs on his body parts.
The police arrested Riya, her boyfriend and so far recovered all the parts barring the lower left leg for which a search is underway.
The police have found some photos and video clips of Rebello's body and claim Riya is now attempting to pass the blame for the killing on her boyfriend.
Though she had earlier claimed that Rebello had allegedly raped her several times, nothing emerged during her medical examination or interrogation, and she has been giving contradictory replies on how the crime was committed.
While both Riya and Chaus have been given police custody till Dec. 16, the minor accomplice was produced before a juvenile court, police said.
( With inputs from IANS )