Malappuram: Two-year-long planning went into the Perinthalmanna robbery in which 3kg of gold jewellery were stolen from the heart of the town on November 21, police revealed. A combined operation between Malappuram and Thrissur police teams busted the gang behind the heist. So far, 13 people, including the nine directly involved in the crime, have been arrested.

Four more people are still at large. The robbery, which turned out to be one of the largest heists in the district in recent times, was initially hatched at the Central Prison in Kannur two years ago. Two petty smugglers from Adivaram in Kozhikode, Shihabudheen (28) and Anas (27), involved in around 20 fraud and theft cases, were the first to plan the robbery.

They hit on the idea after accidentally seeing ornaments from KM Jewellery in Perinthalmanna town being transferred to the owners' house in a two-wheeler. They tracked the movements and found a pattern as the owners lived only a kilometre from the shop.

"When the duo was in prison in Kannur, they shared the idea with a jail mate, Vipin (36), who is serving a life term in a murder case. Vipin, in turn, sought the help of Koothuprambu native Ananthu, who is experienced in gold and money snatching," Malappuram District Police Chief R Viswanath said.

"Under Ananthu's guidance and with the help of his friends, they developed it further. They planned the heist for two years and formed a team of experienced persons to rob the jewellery owners while they were returning home at night," he added.

Once the plan was in motion, the team hired people from Kannur and Thrissur districts. However, only the core team knew the names of other members, so they hid the details from others to keep the plan secret. On the day of the robbery, the jewellery owners were attacked near their home by a nine-member team who arrived in an SVU and robbed the gold.

''Once the robbery was reported, we obtained the CCTV footage of the vehicle they were travelling in and passed the information on to our colleagues in Palakkad and Thrissur districts. We also initiated a vehicle search in Malappuram, Palakkad and Thrissur districts under Thrissur Range DIG Thomson Jose.

"After the robbery, the gold was shifted to another vehicle, and four of the nine were travelling in the first vehicle. They used a fake number plate, but Thrissur police identified the vehicle and took all of them into custody. We found that most of those involved in the hit were habitual criminals," the DPC said. The police said they had recovered 2.2 kg of stolen gold, including melted gold and money from the ornaments sold.

''It was a bit difficult to identify the co-accused while interrogating the five persons arrested on the night of the robbery as they were unaware of the names of other persons. It was from the slang used by other persons they have given a clue about the locations of the co-accused,'' DPC added.

The police have taken the persons in custody from different parts of the state. Those arrested also include Pinarayi native Kizhakkeparambath Ananthu (28), Thrissur Vellanikkara native Kottiyattil Saleesh (35), Kizhakkumpattukara native Mithun alias Appu (37), Pattoorakkal native Kuriyedathu Manayil Arjun (28), Peechi native P Satheesh (46) and Kannara native K Lison (31).

The case was investigated by Perinthalmanna DySP T K Shaiju, CIs Sumesh Sudhakran, A Deepakumar, P Sangeeth, C V Biju, SIs N Rishadali, Shahul Hameed, Perinthalmanna Police, and the DANSAF team.