With claims and counter-claims and new leads emerging in the investigation, the exact motive behind the Sheena Bora murder case remains shrouded in confusion, as investigators continued to probe different angles in Mumbai on Saturday.

According to police, the death threats apprehended by Sheena's brother Mikhail Bora were genuine and he was in Mumbai around April 24, 2012 when his sister was killed.

Since the arrest on August 25 of Mikhail's mother Indrani Mukherjea, wife of former media tycoon Peter Mukherjea, Mikhail has repeatedly claimed that his life was threatened and alleged that his mother had plotted to eliminate him like Sheena.

Living up to his claims, he provided some evidences to the investigators, which Police Commissioner Rakesh Maria said were being verified. The mystery of Sheena's passpost recovered from the Dehradun home of her ex-boyfriend Rahul Mukherjea has been compounded with a new twist.

Officials said Rahul had confronted Indrani about the passport but was informed that Sheena had acquired a new passport and left for the US to pursue studies. Early next week, police intend to recreate the entire crime scene -- from a spot near the National College in Bandra's Linking Road to Raigad and back to Mumbai airport -- that took place on April 24, 2012, when Sheena was murdered, allegedly by Indrani, her ex-husband Sanjeev Khanna and her driver Shyam Rai.

Now, police are pinning hopes on the outcome of the forensic and DNA test reports of the victim and the accused which are expected by next week.

Earlier on Saturday, in a startling development, Raigad police admitted that no case was registered by them after the remains suspected to be of Sheena Bora were found from the murder site in forests near Pen in 2012.

Raigad Superintendent of Police Mohammed Suvez Haque told media persons that he was conducting an inquiry into the lapse and other aspects. Shockingly, however, he said that no crime offence, an accidental death report or a first information report (FIR) was lodged by the concerned police officials then.

On May 23, 2012, a local mango-seller had noticed a partially burnt human carcass and had informed the Pen police outpost. A team of police officials and a doctor had visited the site and conducted a spot autopsy and collected samples of some portions of the body remnants.

"These were later sent to Sir J J Hospital in Mumbai for further analysis after a couple of days. Later, no report was received and no report was sought by police about that," Haque said.

Police had carried out a 'panchnama' (initial observation) of the body and the inquest at the murder site, recorded statements of witnesses and made a diary entry, but no other subsequent procedures were followed.

"I am now inquiring why police (then) did not lodge any offence or ADR (accidental death report) which shall be completed soon and submitted to the seniors," Haque said, adding that he has already submitted a preliminary report to the inspector general of police (Konkan Range).

Responding to Mumbai police's request for help, he said Raigad police have also provided all original documents pertaining to the case to them.

On Friday, the Sir J J Hospital authorities had handed over the samples of bones, nails and other evidence in its possession to Mumbai police, which have been sent for DNA tests and forensic analysis to determine their identity.

The hospital also said it had filed a report in 2012 on how the samples received were charred beyond recognition and they could not identify them.

The development has now led to speculation whether this could be a goof-up or a meticulous cover-up operation, and the then police superintendent of Raigad and his team are under the police scanner for their alleged role and lapses in the matter.

Sheena was killed on April 24, 2012 and her remains were discovered near the Pen forests on May 23, 2012.

Her mother Indrani, her ex-husband Khanna and her driver Shyam Rai have been arrested in connection with the murder and are in police custody till August 31.

On Friday night, in a major breakthrough in the case, Khanna cracked down and confessed to his role and complicity in the crime.