Castro is charged with kidnapping and raping Amanda Berry, Michelle Knight and Gina DeJesus. He's also charged with kidnapping in the confinement of the 6-year-old child police believe to be Berry's daughter.
In charging papers, prosecutors allege Castro lured the women into his car and took them to his home, where he repeatedly sexually assaulted them for a decade.
Cleveland City Prosecutor Victor Perez told reporters in a press conference that the case heads next to the county.
PEREZ: "This case will proceed to the Cuyahoga County grand jury, at which time I expect will result in indictments on these charges, and may result in additional counts."
Castro's two brothers, Pedro and Onil, don't face charges. Deputy Police Chief Ed Tomba said the evidence doesn't point to them.
TOMBA: "There is nothing that leads us to believe that they were involved or had any knowledge of this. And that comes from statements of...victims, their statements and their brother's statements. So as far as what their relationship was, Ariel kept everybody at a distance."
Tomba said law enforcement interviewed the women at length, while still allowing them space because of their trauma.
Castro is also talking. Tomba says Castro waived his Miranda rights and offered police and FBI a detailed statement.
TOMBA: "The major part of the case is what they told us and what the other interviews -- what the suspect told us and what the young ladies told us. Without a doubt. They were the ones that were there...What they told law enforcement was key and that's going to be a key part of the case."
But there are many questions still without answers. Tomba said police were working to learn who is the father of the six-year-old girl.
TOMBA: "That hasn't been determined. There's going to be a paternity test taken. There was a search warrant executed on the suspect to obtain his DNA."
Authorities offered few details on the conditions in which the women lived.
Police Chief Michael McGrath told the Today Show that chains and rope had been found in the home. But at the press conference, officials wouldn't repeat that.
Tomba did say the women were not all kept in the same room, although they knew about one another. And they never left the house, he said, except for two occasions.
TOMBA: "We were told that they left the house and went into the garage in disguise. So those are the two times that were mentioned, or that they can recall."
Tomba said the women had no chances to escape, until Monday night, when Amanda Berry began to scream, and the three women and one child got away.
TOMBA: "Something must have clicked. And she saw that opportunity. And she took that opportunity. I said it the other day and I'll say it today that she is the true hero. She is the one that started this."
Tomba was asked whether police had missed any clues in decade-long search for these three women. He said he'd been part of this case for a long time, and that investigators often asked themselves that question.
TOMBA: "They checked every single lead, and if there was on bit of evidence, one shred of a tip, they followed it up very, very aggressively. So I'd have to say no. In hindsight, we may find out maybe we did, but that's going to be in hindsight."
As the case against Castro moves through the courts, police are still investigating.
A little while before the press conference, Tomba said, the FBI was searching another home on the block. Authorities wouldn't say what they were looking for.
