Before Tamim Ahmed Chowdhury orchestrated Bangladesh's worst militant attack, he sought and won approval for it from Islamic State.
A Canadian of Bangladeshi origin, he was told by his contact in the militant group, Abu Terek Mohammad Tajuddin Kausar, to target foreigners, according to a senior police official who has seen communications between the two men.
Chowdhury, located in Bangladesh at the time, proposed an attack on a Dhaka eatery frequented by expatriates.