When I started writing my story, which is based around the present day in Arizona and New York City, I didn't know that it is (apparently) not used in the US and according to one article is illegal to be used on US soil.
I am seeking one specific piece of data: is it still never used in the US? All the articles I can find say it isn't in use, but the most recent date is June of 2012.
This link says that the case referenced below is the only one ever prosecuted in the US: http://www.nationalpost.com/news/story.html?id=68d60c97-5591-4a48-bced-72b646d9c7f4&p=1
Barring evidence that anything has changed, in the link below an example is given of where a Canadian police force (the RCMP) undertook a Mr. Big sting on Canadian murder suspects regarding a murder that happened in the US.
If I move my interrogation location to Canada, would this be a plausible solution to my conundrum?
Search terms used:
"Mr. Big" United States technique
"Mr. Big" United States illegal
"Mr. Big" "United States" 2013