Excited new homeowners move into their new place in Houston, Texas. But when they decide to do a little work, they make a gruesome discovery behind one of the walls.

It's a bizarre tale that has the whole neighborhood talking: a senior citizen seemingly vanishes into thin air. But then, two years after she disappears, a gruesome discovery. A stunning hidden find. Does it point to foul play?

"It's very troubling to think that could occur right in front of us and we never noticed," said neighbor Roxanne Davis.

Mary Cerruti was quirky and eccentric, and loved by her neighbors.

"She was a very nice, very thoughtful woman," said Roxanne Davis.

Mary lived alone with her cats in a 1930s Craftsman bungalow in a historic neighborhood in Houston, Texas.

"The neighborhood is called The Heights. It's a place where young families live, it's a little bit of an artsy neighborhood," said Houston Chronicle Reporter Emily Foxhall.

Sadly, the charming cottages that dot the quiet street are becoming extinct, replaced by hulking apartments built by contractors with dollar signs in their eyes.

"The apartments were being built around Mary's house, literally in a 'U' shape," said Davis.

Mary was not happy with the new developments, and even voiced her concerns at a meeting of the Houston Planning Commission.

"I think the character of the neighborhood will be damaged," Mary had said at the meeting.

But Mary Cerruti's complaints would go unaddressed. A little more than a year later, she disappeared completely. Where did she go?

"One of the neighbors told me that they had gone by her house and they had noticed that a window had been broken out and a light was on, and they had called the police," said Roxanne Davis.

When cops came to investigate, they were hit by a horrifying smell.

"The stench was apparently unbearable, and it was attributed to the cats," Davis tells Crime Watch Daily.

Mary's eight cats were dead. But there was no sign of Mary.

"The police didn't seem interested in following up on it," said Davis. "There was no movement on the case at all."

Mary Cerruti's house went into foreclosure. Detectives working the case theorized that she since she was going to lose her house, Mary most likely walked away.

"I didn't think that was likely at all, because she had even refused the payout to move away from her home," said Davis.

A few years pass, and the house is sold to a real estate developer who spruces it up. A new tenant moves in, and it was while exploring the attic that he makes a shocking discovery.

911 Operator: "What is your emergency?"

Caller: "So I just called to report this. I didn't know exactly how to do it, but I just moved into this house and I found between two of the walls, I found a human skeleton."

The new tenant was so in shock at finding human remains in the house that he waited a day to call 911.

"He was worried about alarming his wife," said Emily Foxhall.

Even the operator on the other end seemed shocked.

911 Operator: "Did you find the head or the whole body?"

Caller: "There's more than just the head. It looks like a whole skeleton."

"They noticed that there was a floorboard loose, and they looked down beneath the boards, which was between two walls, and saw her skull and some other bones and tattered clothing," said Davis.

Roxanne Davis knew immediately that it was the remains of her sweet neighbor who disappeared two years earlier.

How did Mary Cerruti wind up stuffed between the walls? Was she a victim of foul play? Was it a tragic accident?

"It was very sad to think that she had died alone in her house," said Davis.

Houston Police Detective Timothy Fay was one of the first on the scene.

"There wasn't a whole lot left of the remains, unfortunately, when we started pulling them out of the wall," said Det. Fay. "Quite a number of bones, some clothing, a couple pairs of tennis shoes were inside the cavity as well, and eyeglasses."

Then after inspecting broken floor boards in the attic, investigators can only conclude Mary Cerruti died in a tragic accident.

"It's literally like staying on almost the second floor of a house and having the floor just yanked out from under you without any warning," said Det. Fay.

But Mary's neighbor still doesn't buy that theory.

"I would love to have an explanation as to how investigators seemed to have so casually dismissed this as an accident," said Davis. "How could a human fall into an 8-inch space. I just don't see it."

If it wasn't an accident, how did Mary die?

"I think there's a very real possibility that she was murdered," said Davis.

Roxanne Davis now speculates why her friend may have been a target.

"Perhaps they broke in to rob her and things went wrong," said Davis.

And sadly, Roxanne Davis's own theories, or questions, can't even be answered.

"The bones had all been really badly damaged by animals chewing on them and dragging them away, so the autopsy report couldn't show the cause of death or the manner of death," said reporter Emily Foxhall.

"I am not able to say definitively she was not murdered," said Det. Fay. "However, I don't have enough to say that she was murdered."

So the truth about Mary Cerruti's strange death may forever remain a mystery.