RICHARDSON (CBS11) – Twelve days have passed and there is still no sign of missing 3-year-old Richardson girl.

Sherin Mathews was reported missing by her father Wesley Mathews on Saturday, October 7.

Sherin Mathews (credit: Richardson Police Department)

Wesley Mathews told investigators he punished his daughter for not drinking her milk by sending her outside.

Wesley Mathews (credit: Richardson Police Department)

Nearly two weeks later, investigative experts feel it is what the public is not seeing that could be the most important to a resolution in the case.

“There is no question that most of what the FBI and law enforcement are doing, you don’t know about,” said Dr. Alex del Carmen, a Criminologist with Tarleton State University.

Dr. del Carmen teaches investigators on what to look for in cases like the one involving Sherin Mathews disappearance.

“It’s a very disciplined, organized response,” said Dr. del Carmen.

All of the items seized by police and the FBI are very standard according to Dr. del Carmen.

“Investigators are going to look at every single angle,” said Dr. del Carmen.

He trains investigators to look in places like washers and dryers for possible residue.

Digital evidence like emails, texts, google searches in any case helps investigators understand if there is any motive. Dr. del Carmen said swabbing vehicles is also standard but has challenges.

“If you find the little girl’s DNA in one of the cars, what’s the big deal, you’d expect that to happen right?” questioned Dr. del Carmen.

In any case, Dr. del Carmen said investigators must decipher DNA evidence to understand where it should be and where it should not.

All of this investigative work takes time and the public does not often understand.

“There are hundreds of people, not a dozen, but hundreds of people that are working on this case right now, 24/7 trying to piece it all together because there is the presumption that she in fact is alive,” said Dr. del Carmen.

But looking at past statistics involving older and similar events, 12 days missing is a lot of time, said Dr. del Carmen.

“The clock is against the individual coming out of this thing alive,” said Dr. del Carmen. “The odds are against her.”

Wesley Mathews was arrested and charged with child neglect the day he reported Sherin Mathews missing.

He has since bonded out. He was forced to give up his passport and wear an ankle monitor.