US suspects that Pakistan's powerful spy agency ISI could be behind the attack on its Embassy in Kabul this week and is looking for direct evidence in this regard. A senior US defence official said that given the ISI's history of supporting and sheltering the Haqqanis, it was “almost reflexive” to see if the spy agency had any role in the latest Kabul violence that left 27 people dead.The Wall Street Journal reported today that the American suspicions are being partly fuelled by growing concerns that deteriorating bilateral relations, and the withdrawal of troops from Afghanistan, may be pushing elements of Pakistan's Inter-Services Intelligence spy agency to more closely embrace the Haqqani network, blamed for this week's violence and a spate of attacks in and around Kabul.