"We have seized many weapons and we will zero in the right weapons after the ballistic examination," he said.
The search was conducted in the presence of a 10-member Italian delegation, including two ballistic experts who were flown in from Rome this morning.
Italian Consul General Giampaolo Cuttillo was also present during the search along with his country's ballistic experts Major Flebus Luca and Major Fratini Paolo.
The SIT of Kerala police began the search around noon with forensic and fingerprint experts also on board the vessel berthed.
The two arrested marines - Latore Massimiliano and Salvatore Girone - have been charged with murder in connection with the killing of the Indian fishermen on Feb15.
The weapons used by the six marine security personnel on board have been seized and would be sent to Thiruvananthapuram forensic laboratory, Kochi commissioner MR Ajith Kumar, heading the SIT, said.
Besides Kumar, Kollam Police commissioner, Debesh Kumar Behera, along with a team of police officers were present on board the tanker during the search.
Addressing a meet-the-press programme of the Ernakulam press club, Chief Minister Oommen Chandy said government would make all efforts to ensure that families of the two Indian fishermen get the maximum compensation.
The probe was in the right direction, he said, adding, the Centre was extending all cooperation to the state. Since the state government had taken a strong stand the Italian government was cooperating with the probe, he said.
The incident had occurred in Indian waters and the Italian marines should be subjected to Indian laws, he said. The Kerala High Court had yesterday ordered arrest and detention of the vessel at Kochi port oil terminal till Monday evening.