Karnataka Chief Minister S M Krishna on Sunday described the killing of Janata Dal (United) leader, H Nagappa, by forest brigand Veerappan as an "unexpected" development and said all out efforts would be made now in collaboration with Tamil Nadu to capture the outlaw.

Speaking to reporters in Delhi, Krishna said he spoke to Tamil Nadu Chief Minister Jayalalithaa soon after Nagappa's body was recovered and she agreed to extend her state's cooperation to nab Veerappan.

"This is an emotive issue. None of us expected this development," he said.

"From now on, all out efforts will be made with the help of Tamil Nadu's Special Task Force and Central govenment forces to nab Veerappan," he said.

Krishna is returning to Bangalore on Monday morning.