The US investigators believe some elements in Pakistan's ISI could be linked to American terror suspect David Headley who is currently in FBI custody for trying to plot attacks in India. The investigators made this assessment on the basis of the arrest of two key persons in Pakistan. PTI quoting sources said, Illyas Kashmiri, a former Pakistani military officer who has become a militant commander associated with both al-Qaeda andLashkar-e-Toiba(LeT), is one among them. They have also zeroed in on a Pakistani national who is suspected to be a key link between LeT handlers and Headley and his Pakistani-Canadian associate Tahawwur Hussain Rana.The sources said, India and the US are in constant touch on the Headley case and Washington has conveyed that within a week there could be "authentic" information whether they were involved in the attack. intl more