The body language thing really bothers me.

Personally, if someone accuses me of lying, but I am actually telling the truth, I immediately start acting like a liar. It's really embarrassing and hard to explain. I can't believe such a seasoned reporter is leaning so hard on "his face went red."

What's also worth noting is that they were not alone in the room, talking privately. Everything being said could presumably be heard by Back's business associates as well. Some of the questions could well be enough to cause embarrassment or unease on that account.

Yea pretty similar idea to a polygraph test which for years was called a "lie detector."

In reality, they measure a bunch of things that may indicate lying, but they are just as likely to indicate that a person is nervous or reacting to the fact they're being tested at all.

They're typically inadmissible in court these days, however, there is still a pretty solid amount of blind trust in their results.

That part of the article gives a similar "lie detecting" hypothesis, just without the machine.

In fact, we are incredibly bad at telling lies from the body language of people we don't know well. Pretty much all the "well known" tells are sheer and utter bullshit that at best tells you if a person is stressed. That may or may not mean they are lying, but unless you know that person well enough to know if they have specific tells that correlates with lying for them, your odds are poor.