Additional Director General of Police (northern range) N. Shankar Reddy visited the spot at Parad, near Panur, where bombs had exploded on Thursday night, leaving four persons injured.
The police had raided the area soon after the explosion and found six bombs and five bomb-making containers. Mr. Reddy said the initial investigation provided clues to the explosion, which could have taken place while making bombs.
The case will be investigated by Panur Circle Inspector Jayan Dominic under the supervision of Thalassery Assistant Superintendent of Police T. Narayanan. Mr. Reddy said the investigation would be handed over to any other agency only if the situation demanded so.
Meanwhile, the four persons injured in the incident are being treated in a private hospital in Kozhikode under police custody. They have been identified as Munawar (18) of Parad, Muhammad, P. Afsal (19), and Jasim V.V (20).
Cases have been registered against them under Sections and 3 and 5 of the Explosive Substances Act by the Kolavalloor police. One of them is said to be a worker of the Social Democratic Party of India, the police said.
The Bomb Detection and Disposal Squad examined the area on Friday morning. It retrieved materials used for making bombs from the area.
Five platoons of the Armed Police are deployed in the area. The explosion had taken place a few kilometres away from the house of Minister for Agriculture K.P. Mohanan. On account of a wedding ceremony that is to take place in his house on October 6, the police will be deployed in the area as Ministers, including the Chief Minister, are expected for the function, the police said.