The police arrested a target killer of Muttahida Qaumi Movement-London (MQM-L) with illegal weapons here on Tuesday. The police said that on a tip-off, it conducted operation at Mehrunnisa Road in Karachi. During operation, a target killer of MQM-L wanted by police in several cases was apprehended with illegal arms. The police confiscated the recovered weapons and after registering a case against the detainee have started an investigation.