The CPI-M on Friday demanded to know why police were lax in Assam's Kokrajhar district - where terrorists killed 13 people -- despite knowing it to be "terrorist infested".Condemning the terror attack, the CPI-M said: "This area has been known for long to be terrorist infested and it is strange the police administration and the BJP government did not take adequate measures to protect the life and property of the people."The CPI-M said the security apparatus must be strengthened to protect life and property and all efforts must be made to identify and punish the guilty who carried out the killings.