The discovery in a Cleveland residence of three women who had been missing for a decade has many people wondering how it’s possible they were confined so long without anyone knowing. Dave Perry, a former detective with the Toronto Police homicide and sex crimes unit, shares his insights.

On Monday night, police received a frantic 911 call from Amanda Berry, a woman who said she had escaped after being kidnapped and held captive in a home near downtown Cleveland for a decade.

The call led police to Berry and two other women in the home. Michelle Knight was 20 when she disappeared in 2002, while Gina DeJesus was 14 when she went missing in 2004. Berry was 16 when she vanished in 2003.

Anyone able to keep three abductees secretly confined for as long as 10 years, would have had to be extremely disciplined and well-prepared, Perry told CTV’s Canada AM on Tuesday.

The abductor would have had to do an incredible amount of preparation in order to maintain secrecy for so long, he said, including turning his home into a fortress that appeared nondescript from the outside, but was virtually inescapable from the inside.

He would also likely need to have restraints in place and the means to keep his captives completely isolated from the outside world.

"What it tells me from listening to the 911 tape is the accused did a very good job of confining these women," Perry said.

"No one in the neighbourhood knew these women were living there. Amanda couldn't get out of the house alone, she had to scream for help and get neighbours to assist her, so clearly this house was designed to hold women captive and that was obviously done through some tremendous planning and efforts."

The women were all taken within a few blocks of each other, and near the home where they were found. Perry said that should have tipped police off to the fact they were searching for a serial predator who had been targeting women in the area, likely lived close by, and was working alone.

"Women don't just vanish off the streets, and when they start to, we have to get very concerned. And when they start to in a pattern like this, we have to have a look and wonder what kind of a serial predator we have operating in the area," he said.

A six-year-old was also found in the home but police did not disclose the child's identity.

Police have arrested Ariel Castro, a former bus driver who lived at the residence, and his two brothers.

With files from The Associated Press