(CNN) -- In retrospect, there were plenty of signs that something was wrong: reports of a naked woman roaming the backyard. A child peering from an attic in a house where no children lived. Sealed windows, muffled screams and accounts of what sounded like people pounding on the walls from inside.
But the incidents were spread out over years. Even now, it is not precisely clear who saw what or when. Attempts to report the odd occurrences to the police seem to have been sporadic, and the police response appears to have been equally limited.
So, after a while, 2207 Seymour Ave. would lapse back into silence, with no one opening the door to knocks and nothing amiss that a fresh coat of paint could not fix. It was indeed so silent much of the time that some neighbors thought no one lived there.
The house that Ariel Castro bought more than 20 years ago for $12,000 is in itself unremarkable. Built in 1890, it is situated in one of Cleveland's oldest neighborhoods, Tremont, and real estate records indicate that the house underwent a major renovation in the 1950s.
With a little over 1,400 square feet of living space, it is neither unusually large nor small. It has a detached garage and two porches: the front one small and open, the back one enclosed. It holds two floors, an attic and a basement. If you walked in through the front door that Amanda Berry used for her escape, you would be greeted by a staircase going up directly ahead of you and a small living room to the left.
Tito DeJesus (no relation to one of the women being held, who has the same surname) walked through that door. "He kept his musical instruments in the living room," DeJesus said of the owner, Castro. "He was a bass player."
As a fellow musician, DeJesus went inside the house three times to see Castro. He described a few simple pieces of furniture, a sofa and a chair or two. He notes that Castro kept his bass, amplifier and speaker out in the living room, where he could easily pick them up and play, and that that room led directly into the dining room, and from there, a closed door led to the kitchen in back. The house was reasonably tidy when DeJesus stopped by and "quiet ... like it was empty."
Upstairs, where one witness occasionally saw a woman looking out from a window before it was covered over, real estate records suggest there are four bedrooms and the only bathroom.
No one who has been voluntarily up there has come forward with any details of the architecture or descriptions of the attic. And nothing is known about the basement, which a witness says can be reached by stairs that run underneath the staircase that leads to the second floor.
A local construction and home repair worker who has been in the neighborhood for years says typically, basements here are made of "unfinished concrete blocks ... or sometimes cut stone" and hold "the guts of the house," meaning the furnace, water heater and sometimes the electrical boxes. Usually, due to the sandy nature of the surrounding soil, basements here are made smaller than the houses above, and he adds, "they all leak."
That is what we know about the Castro house.
But it is the unknowns that have the neighbors sitting up late, talking, and wondering how it could be. Where were the chains and ropes that police say were used to bind those three women? Are the stories of padlocked doors true? Were the women and that child kept together or apart? What, if any, sort of mental games were used to dissuade them from escaping a place that from the outside looks so easy to slip away from?
That last question may prove very important in solving the mystery. There have been cases in which kidnappers have instilled such fear of reprisal in their victims -- by making all pay painfully for the transgressions of one -- that the hostages wind up essentially forced to control each other.
All that is certain is this: The evidence suggests that for a long time, these women were held undetected inside a seemingly normal house, on a normal street, while the homeowner saw neighbors, entertained their kids, ate at McDonald's and appeared perfectly normal.
That does not make the house on Seymour Avenue haunted, but it certainly makes it haunting.