To be honest, that has been done so frequently that it is difficult to keep track. The ISI has been active in a number of locations; with elements of SIMI, although that was originally an activist Muslim forum not connected to terror; with elements in Bangladesh, who were responsible for activating Muslim Indians, particularly in Bengal and in Bihar; with the Nagas and the Mizos, much earlier, operating out of Bangkok; with a varied lot of tribal malcontents in the north-east; with other tribal groups in Myanmar, acting against both Myanmar and India.
The most horrible occasion was the attack on Mumbai, although the attack on Parliament came a close second. The whole world knows by now, down to identification of one terrorist's home town and parents, to the names of the handlers, to the details of messages exchanged during the attack, everything. But Pakistani authorities are like the ostrich; once it hides its head in the ground, it thinks nobody can see it, as it can see nobody.
Just go and ask around. Your reputation will speak for itself, ours will speak for us.