Donald Trump released a scorching attack ad against Hillary Clinton on Instagram Tuesday. 

The short video features a black and white image of Bill Clinton chomping a cigar. Then, a voice: 

That’s the voice of Juanita Broaddrick. She accused Bill Clinton of sexual assault in 1999. 

The video ends with a picture of the Clintons with the caption, "Here we go again?"

This particular brand of smear is likely the work of oppositional researchers. To many, they’re known by another, more colloquial name: dirt diggers.

Who are the people doing the digging, and what impact can their information have on a campaign?

For answers to that, Take Two spoke to Alan Huffman. He’s a veteran researcher and co-author of the book, “We're with Nobody: Two Insiders Reveal the Dark Side of American Politics.” 

I'm sure this is not what you have printed on your business card, but you are basically a dirt digger, yes? How long have you been doing this?

About 25 years. Yeah, that is what we do. We dig for dirt. 

How does a person wind up in a field like this? I can't imagine you as a little boy saying, 'when I grow up I want to find the worst things about people so others can use it to their political advantage,' right?

My research partner, Michael Rejebian and I were both investigative reporters originally. That’s how we were trained. We both sort of segued to politics. After we left, we both decided that we had specialized skills which were understanding how to find things out about people that were running for elected office. It was fascinating to us: just finding out who are these people and what makes them tick, and then turning it over to the voters and finding out what matters to them.

How do you go about looking for dirt?

We start out like anyone would just Googling and finding out what all the easy stuff is. Then we start building a portrait of the candidate and finding out where all the most interesting details are, where the gaps are, and then we go about filling those. There’s still an aspect of this that’s two guys in a rented Hyundai roaming around the country getting the goods on the politicians. It’s a mix of things: interviewing people, you may be talking to some guy that’s sitting on the porch of a trailer with a shotgun because he thinks someone’s going to kill them for talking to you. And then you may spend days just going through moldy records in some courthouse. You put all of this together and connect the dots, and you see the strong suits and the weaknesses of both your candidate and their opponent.

Press the blue play button above to hear the interview. 

(Answers have been edited for brevity.)