WICHITA, Kan. -

The defense in a Dodge City child death case is arguing to allow polygraph test results to be allowed in court.

Three year-old Natalie Pickle died in 2008. She was in the care of her mother's boyfriend at the time who told police Natalie fell off the bed.

But medical experts testified her head injuries were severe and disputed the boyfriend's claim.

The case could change the entire playing field in one attorney's words and will almost certainly end up at the Kansas Supreme Court.

Polygraph tests are not admissible in Kansas courts. They are used by police and attorneys, but not in court

There's a reason. They're not always accurate.

Eyewitness News talked to long time attorney Stephen Joseph about this case who says there's a lot to consider with polygraph tests.  He said the results depend on the operator number one, but also the person taking it.

They do not work like you see in the Hollywood.  The tests do not tell you whether a person is telling the truth. Joseph said they tell you what that person believes.

"I'm afraid most people think the poly or lie detector test tells you what the truth is…that's not what it is. It tells you how this person is physically reacting…whether he feels guilt or doesn't feel guilt," Joseph said.

He also brings up another point.

"I always tell defense attorneys like myself to be careful what you wish for because if it's admissible for the defense why wouldn't be admissible in the prosecution," Joseph said.