NEW DELHI: The Government Railway Police (GRP) have recovered the knife allegedly used in the murder of a man by a co-passenger on a Mumbai local train, officials said on Tuesday.According to police, a viral video of the incident played a key role in the recovery of the alleged murder weapon.A restaurant manager in Borivali approached the police after watching the clip and informed them that one of his employees had found a knife in an alley near platforms 2 and 3 of Borivali railway station.Unaware of its possible connection to the crime, the employee took the knife to the restaurant’s staff room and kept it in a cardboard box. Officers later recovered it and concluded that it was the weapon used in the stabbing.Earlier, the accused, Roshan Suvarna, reportedly confessed during custodial interrogation that he had been carrying the knife in his bag for the past four to five months. He claimed he had taken the sharp, maroon-handled knife around seven months ago from an Amazon warehouse where a friend worked.Police said Suvarna told investigators that he threw the knife away after getting off at Borivali railway station. However, despite searching the route indicated by the accused, officers were initially unable to recover the weapon.In a related development, a magistrate’s court on Tuesday extended Suvarna’s police custody till July 6 after investigators sought seven more days to continue their probe.Seeking the extension, police told the court they needed more time to determine why Suvarna had been carrying the knife for several months, whether he had used it in any previous offences, and to establish the motive behind the crime.Opposing the plea, advocate Jaywant Patil, appearing for the accused, argued that police had cited the same grounds while seeking the earlier remand and had already been given sufficient time to ascertain the motive.After hearing both sides, the court extended Suvarna’s police custody till July 6.Suvarna was arrested for allegedly stabbing 22-year-old Mayank Lohar to death inside a first-class compartment of a Mumbai local train between Andheri and Borivali last week following an argument over keeping the door shut.