(CNN) It's been two days since 4-year-old Maleah Davis vanished. Two days since the young girl, her brother and her stepdad were abducted by a trio of mysterious men, the stepfather said.

Yet for reasons still unknown, everyone but Maleah was released safely, the stepfather said. And the trio of men are nowhere to be found.

Now Texas authorities are scrambling to find Maleah, who was recently ill and has endured multiple brain surgeries throughout her young life.

An Amber Alert has been issued for 4-year-old Maleah Davis.

"I realize there's a lot blanks in the story" given by the stepfather, Houston police Sgt. Mark Holbrook said. He said detectives hope the public can help them "fill in the blanks."

Here are the pieces of the puzzle we have so far:

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