Creating accurate timeline critical in case of missing Richardson girl

A former FBI official said its critical authorities create an accurate timeline in cases like the one involving a missing 3-year-old Richardson girl.

While ground searches continue daily looking for any traces of Sherin Mathews, behind the scenes other evidence is already being processed.

"A lot of times particularly in looking for a child where there are some things that probably have been missed, or were overlooked, now you go back from the beginning and you build upon the case to make sure that you haven't missed anything," said Danny Defanbaugh, former FBI Dallas chief.

One key piece of evidence is the Acura MDX that police say was driven away from the home for one hour on the morning Sherin disappeared. It was one of three vehicles towed from the family home hours after Sherin was reported missing.

Court records show a navigation unit, likely from the Acura, was sent to the FBI lab in Quantico, Virginia. Deffenbaugh says the lab is considered the most sophisticated forensics lab in the country and the experts there should be able to reconstruct where that vehicle was during the time period in question.

"It can tell you many times, depending upon how far back you have to go, how many miles the vehicle had gone and or some have GPS type instruments that will tell you where they have been," Defanbaugh said.

Sherin's 37-year-old father, Wesley Mathews, is charged with child endangerment. In the 11 days since he reported his daughter missing, neither he nor his wife has talked publically about the search for her.

Both parents have hired attorneys and police say neither is cooperating with investigators.

"The media is critical in putting forward the child's face in front of the public," Defanbaugh said. "The media is your best friend as far as keeping that case in that matter to the forefront and keeping it alive until the child can be found."