Definitive explanation of the line, “…picking your feet in Poughkeepsie.” from “The French Connection.”

Question

So in the 1971 film, The French Connection, Gene Hackman’s character Jimmy “Popeye” Doyle utters this semi famous bit of dialogue; YouTube video clip at the end of this question:

All right! You put a shiv in my partner. You know what that means? Goddammit! All winter long I got to listen to him gripe about his bowling scores. Now I’m gonna bust your ass for those three bags and I'm gonna nail you for picking your feet in Poughkeepsie.

There are tons of wacky Internet theories on what that “…picking your feet in Poughkeepsie.” line really means. The most sane and rational meaning is that the line is simple a confusion/interrogation tactic where someone utters accusatory nonsense like that to confuse the person they are interrogating so that when they ask a real question, their defenses will be down and they will utter “the truth” or confess to a crime.

But is there any documented definitive explanation of the meaning behind that bit of dialogue from anyone directly involved with the film? The closest reference I can find online is from a discussion on MetaFilter from 2007 that references the commentary on the DVD. But that answer contains a summary of what the DVD commentary said and not a direct quote from someone including their name.

Can anyone here provide some more solid references to the “…picking your feet in Poughkeepsie.” line?

Answer 1

From IMDB trivia section for the film re the DVD commentary:

The scene where Doyle and Russo chase down the dealer near the beginning and Gene Hackman shouts out his famous question "Did you ever pick your feet in Poughkeepsie?" is based on actual "good cop/bad cop" interrogations by the real "French Connection" detectives, Eddie Egan and Sonny Grosso according to William Friedkin in the DVD commentary. Grosso would gingerly ask a suspect direct questions about his crimes, then Egan would always butt in and yell unusual questions like the Poughkeepsie one. The suspect would get so rattled by Egan's offbeat questioning that he felt more comfortable answering Grosso's, thus, tending to eventually incriminate himself.

If taken at face value, that means the line isn't supposed to make sense, in real life or the movie.