With the killing of top Manipur police commando N Lokhon Singh earlier this week, the number of high-profile police officers killed by militants in the region over the past six months now is three. Last December 2005, the Manipur Inspector-General of Police (Intelligence), Tunglut Thangthaum, was killed along with a havildar in an ambush.In November the same year, the former Nagaland Director-General of Police, H Hesso Mao, was shot dead at his Kohima residence. In Thangthaum’s case, the assailants said it was a ‘‘mistake’’, Mao was allegedly shot for failing to meet extortion demands.But for Singh, the People’s Liberation Army, which claimed responsibility for the attack, said it was a punishment for his alleged corruption and womanising.Singh was ambushed by PLA insurgents in Thoubal district where he was conducting frisking operations; he was heading the commando unit of the Thoubal police. Five other police personnel and one militant also died in the attack.