A "KILLER" dad who took part in a TV appeal calling for the safe return of his pregnant wife and kids may have given away nine tell-tale signs of his guilt.

Seemingly calm Chris Watts appeared on US TV to claim he had absolutely no idea where his wife and kids had disappeared to hours before "confessing" to cops.

Shannan, who was 15 weeks pregnant with her third child, disappeared from Frederick, Colorado, on Monday with daughters, Bella, four, and Celeste, three, known as "Cece".

Her husband was filmed outside the family home as he pleaded for the safe return of his missing family - hours before reportedly confessing to killing them.

He looked into the cameras as he said: "I have no idea, like, where they went. I don't feel like this is even real right now. It's like a nightmare I can't wake up from."

During the interview - now seen around the world - he told how he called in the cops after learning his house was deserted.

However, just hours later legal sources claimed he had confessed to killing his family and is now behind bars awaiting charges.

Here renowned body language expert Judi James analyses his interview and reveals any clues which may have given him away.

Judi said: "Body language is not a precise science and using it in legal cases like this one can be especially difficult as lying signals can depend primarily on guilt-based responses.

"This means an honest person lying about a very minor misdemeanour can easily look more guilty than a murderer who might be incapable of feelings of guilt or even who believes their actions were justified.

"The other feature of this footage is that - like a lot of people wanting to look honest - he clearly sticks to the true events of his story.

"The narrative here is about the friend calling him and how the house was empty when he got there.

"These are likely to be events that he really did experience, so the verbal version and the non-verbal signals would be more likely to be congruent and it is often this that gives an impression of being cool and collected.

"His arms are folded which would help avoid any gesticulation that might be incongruent to the verbal narrative.

"Although this creates a physical 'poker face' his emotions still emerge via a side-to-side swaying of the body and a shaking of the head as he talks.

"The head shake will look like a 'no' gesture but it can also be used to register disbelief. His eyes move to his right as he relates his story before coming back to perform sustained bouts of quite level eye contact.

"The sideways glance can suggest someone is accessing creative thinking but this trait isn't true of everyone.

"Eye contact is often seen as a signal of truthfulness but it is often acted quite effectively by people who are guilty too.

"His blink rate isn't accelerated to a point where you might suspect anxiety or fear but his breathing does sound a little shallow, which can happen under pressure.

"However that pressure could be caused by either guilt or by anxiety about a missing family."

Cops revealed Chris Watts made the shocking confession late yesterday, according to Denver7. The police later tweeted Watts is being held at the Weld County Jail. He has not yet been charged.

The FBI and Colorado Bureau of Investigation are also investigating the incident, local legal sources told Denver7.

During the interview, Watts claimed he texted his wife numerous times but didn't get any response which he thought was odd. He then raced home but found it empty and quickly filed a missing persons report with the cops.

He claimed: "I was trying to get home as fast as I can, I was blowing through stop lights. I was blowing through everything just trying to get home as fast as I can because none of this made sense.

"I don't feel like this is even real right now. It's like a nightmare I can't wake up from."

The Frederick Police Department confirmed they had made an arrest "in connection to the missing person's case" of Shannan and her daughters.