Ever since fire destroyed Seneca's grade school on March 10, Chad Miller says his son Damon has been a suspect. He says the accusations and harassment from friends prompted the 14-year-old to take a polygraph test.

Damon failed, but Chad says it wasn't because his son was lying. In fact, he said he questioned the man who conducted the test.

"And I asked him specifically, how old is that machine and his reply was, and I quote, 'older than dirt'," Chad said.

But Lt. Phil Blume with the Shawnee County Sheriff's Office says polygraph machines are tested regularly to keep up with the manufacturer's requirements.

And that it does not determine if someone is lying. Instead, it monitors physiological changes in a person that indicates deception.

"For our criminal cases it may be a situation where an investigator has reached a stalemate and may feel that a polygraph may be beneficial in assisting in a case," Blume said.

But he says polygraph tests play a small role in investigations. That's because in Kansas the charts are not allowed in court as evidence, unless the state and defense agree before the test that it can.

"But interviews prior to a polygraph can be admissible," he said.

But regardless what evidence is used against his son in the Seneca investigation, Chad says he knows Damon is innocent.

"But it ain't over, not by a long shot," Chad said. "It's just begun as far as I'm concerned."

Damon is in a juvenile detention center in Lawrence on arson charges. His hearing is set for Wednesday morning.