The CIA / U.S. military have been involved with electronic warfare for a long time. I would disagree and say they're at least as innovative and perfectly capable of carrying out something like this. If it was a US operation though, I would probably add the NSA to the mix as well, since they likely would have had involvement at some point in the process. In either scenario though, it would likely involve contractors of some sort, if only for the specialized Siemens knowledge that would be required.