[don-o]

"But AP traced their government Internet connections — logged by the website over five years — and reviewed their credit-card transactions to identify them."

Does this pass the smell test?

[Lazamataz]

Yes. Unless they proxied outside of the .gov domain — something that if I am not mistaken, borders on criminal behavior — then the .gov domain would be clearly observable. Ashley Madison would log it as a .gov visit. Then the reporters merely need scan the data dump for .gov entries.