Police have made two further arrests after a man was stripped naked, tied up and beaten during a 50-hour hostage ordeal.
Two men, aged 28 and 19, were arrested on suspicion of kidnap after CCTV was released in a public appeal for information.
The pair are being questioned at a south London police station.
Metropolitan Police said they are still hunting for another two suspects in connection with the "vicious and prolonged attack", which may have involved up to 12 attackers.
The 24-year-old victim, wearing a £9,000 Rolex watch, was lured to a house by two acquaintances while walking down London Road, Croydon, at 2pm on December 4.
He was ambushed by a group wielding knives and guns who subjected him to a terrifying kidnap ordeal which saw him stripped, tied up and threatened with a gun.
The captors forced the man to ring his parents and make a ransom demand for his release, which they could not pay.
Instead, two of the gang took his keys and burgled the couple's home,
grabbing cash, designer handbags, sunglasses and further Rolex watches.
Footage showed one suspect, a black man with dark facial hair wearing a high-visibility jacket over a parka, walk to the door and spot the camera.
He returned with an accomplice wearing an orange high-visibility jacket to enter the property, with both men covering their faces.
The victim finally managed to escape after being taken to a cashpoint to withdraw money.
His tormentors waited in the vehicle, apparently out of fear of being captured on CCTV.
Two men aged 39 and 58 were previously arrested on suspicion of kidnapping and bailed to early January.