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HUNT COUNTY (CBS11) – The search for a missing former Dallas firefighter hit a wall on Wednesday as investigators spent the entire day scanning an area northeast of Quinlan, finding no sign of the man.

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Investigators said Michael Chambers, 70, was last seen on Friday, March 10. Security camera footage from a local Walmart appears to show Chambers at the store the same day.

On Wednesday, the Hunt County Sheriff’s Office searched a five-acre area along with the help of more than 75 volunteers.

Despite the thorough search, investigators found zero evidence of Chambers.

“It just doesn’t feel like something that could be happening to our dad,” said Cheri Haynes, a daughter of Chambers.

Haynes and Suzy Losoya want their dad back.

“That’s not your typical 70-year-old,” said Losoya. “You’re not looking for a slow, little, geriatric patient. This guy’s is strong.”

Michael Chambers (credit: Hunt County Sheriff’s Office)

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Investigators found a small amount of blood in his shop, but not other evidence or anything to suggest foul play.

“It’s a very sad mystery,” said Sgt. Jeff Haines, with the Hunt County Sheriff’s Office.

Haines said they have zero clues as to what happened to Chambers and as of now, they are treating it purely as a missing person case.

“It’s disappointing because we want to give the family some kind of answers,” said Haines.

With the help of multiple agencies including the Texas Game Warden, crews combed line-by-line and area just outside of town and left empty-handed.

“Time becomes more critical because your information becomes more stale,” said Haines.

Haynes and Losoya said the hardest part right now is explaining the situation to their kids.

“They want their pawpaw. They need their pawpaw back,” said Losoya

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The Hunt County Sheriff’s Office said it is done searching the area it sifted through on Wednesday. It is now regrouping on the next move and hoping for a lucky tip.