Re the bank transfer: in this country, there is NO BANK SECRECY at all. The cops would be able to get a warrant or whatever and whoever tried to pick up or re-transfer that money would be caught. The banks answer to LE in America. So he really must be stupid if he thinks he'd ever see that money.
That's exactly why it's not a loner. An organized terror cell would have a lot more leverage than a lone gunman and would have a better chance of pulling this off. The threat would be greater and potentially could become more widespread