A blast rocked the Collectorate premises on Tuesday afternoon but no casualties or damage were reported, police said.
“No one was injured,” district collector A Shainamol said.
Three cars were damaged in the blast. The car under which the bomb was placed was reportedly hired by the District Medical Officer (Homeopathy) Reji Kuzhiyellil.
Officials said they found a paper box, a pen drive and a letter reportedly written by an organisation called the Base Movement at the site of the blast. The letter – which also carried a photograph of former al-Qaeda chief Osama Bin Laden – detailed alleged human rights violations in the country, including the killing of Dadri lynching victim Mohammad Akhlaq on rumours that he had killed a calf and eaten beef.
Malappuram Superintendent of Police Debesh Kumar Behra, who reached the scene soon after the explosion, told reporters that it was a ‘pressure cooker bomb’ and apart from the vehicle, no other damage or casualties were reported.
“A box with a name slip of ‘The Base Movement’ has been recovered from the site. It seems this organisation was involved in such activities in Nellore, Mysuru and Kollam in the past,” he said, adding that a special investigation team will be set up to probe the incident.
District Collector A Shinemol, who was also at the scene, incidentally held the same position in Kollam last year when a similar explosion took place at the district headquarters there.