What happened? Law enforcement expert weighs in on Sherin Mathews case

RICHARDSON- We now know, the body Richardson Police found on Sunday was that of three-year-old Sherin Mathews, who'd been missing since October 7th.

Now, we're learning what her father told police during an interview on Monday.

Cops released an "arrest warrant affidavit" about the conversation they had with Wesley Mathews.

He said he "physically assisted" the girl in drinking her milk, then she started to choke,  and eventually he could no longer feel a pulse.

That's a big change from what he initially told cops.

"Criminals in general aren't usually mad that they did what they did, they're mad that they got caught," said Rich Emberlin, who worked for the Dallas Police Department for 30 years. "I think he's trying to build a case for the least amount of culpability because the story keeps changing."

When Sherin was first reported missing, her father told cops he'd told the child to stand outside alone at 3 a.m. as punishment for not drinking her milk.

He claimed Sherin was gone when he went outside to check on her 15 minutes later.

After two weeks of searching, police found her body in a culvert less than a mile away from the Mathews family home.

"Police are fallible, canines are fallible,"Emberlin said. "Maybe that child wasn't there when they did their initial search...you just never know in this kind of situation. But I know that area was scoured."

Police are still investigating what exactly happened that night at the Mathews home, but there's a good chance this story could change again.

"I think a lot will come out after the autopsy and you'll probably see a different set of charges," Emberlin said.