This is very confusing because some comment was made re the Flynn logistics at the time of the call - and it was said that Flynn was in a foreign country (not Trump Tower).
I thought that sounded weird, but nobody questioned it.
However, Clapper and Brennan had been surveiling Trump since Bush 41; in Trump Tower.
I haven’t been able to find anything that refers to Flynn’s location at the time of the call. Thursday, December 29th, was the day Obama placed the sanctions on Russia, and it is cited as the day they claim Flynn spoke to the Russian Ambassador about the sanctions. Now frankly, Obama placed those sanctions on Russia for meddling in the U.S. election, but no evidence has ever been proven that they ever did interfere.