Four people have been detained for questioning in connection with the low-intensity bomb blast at a Bengaluru eatery, police sources said on Saturday.Sleuths of the Central Crime Branch probing the case are interrogating the four, picked up from Dharwad, Hubballi and Bengaluru "at length", the sources said.Bengaluru City Commissioner B Dayananda said investigation into The Rameshwaram Cafe incident, caused by an Improvised Explosive Device (IED) on Friday afternoon in which ten people were injured, is in full swing."Several teams are working on different leads obtained so far," he said."Keeping in mind the sensitivity of the case and the security concerns, media is appealed not to indulge in speculation and co-operate," Dayananda said.Meanwhile, security has been tightened across the state, especially at Kempegowda International Airport, following the incident in Brookefield area in Information Technology corridor in east Bengaluru.The Bengaluru Police has registered a case under the stringent Unlawful Activities (Prevention) Act and Explosives Substances Act in connection with the explosion at the popular quick-service eatery.