Kolar, Nov 28 : Three police officers, including a Police Sub-Inspector (PSI), have been booked in connection with the lockup death case in Karnataka's Kolar district, police said on Tuesday. The action was taken following a report submitted by Deputy SP Nandakumar in connection with the case. The FIR has been filed against PSI Pradeep Singh and police constables Manjunath and Mahantesh Poojar, who are attached to the Nangali police station in Mulbagal. The accused officers had taken Muniraju and Balaji, residents of Madanapalle in Andhra Pradesh, into custody for inquiry. The police said that Muniraju and Balaji were brought to the police station on September 17. On October 1, Muniraju died in a private hospital. The investigation disclosed that the victim, Muniraju, was kept at various places for 15 days for questioning before his death. A probe into his death revealed that the officers were conducting an inquiry without notifying senior officers. Kolar SP Narayana suspended the accused PSI and two constables. /IANS