Castro did not have a chance to talk to his two brothers, who were arrested and cleared without charges, DeMetz said.
The women and Castro have given lengthy statements to police that have helped build their case, said Deputy Police Chief Ed Tomba.
None of the women, though, gave them any indication that Castro's two brothers, who had been in custody since Monday, were involved, Tomba said. Prosecutors brought no charges against the brothers, citing a lack of evidence. The brothers appeared in court before Castro, on unrelated charges, and were in the process of being released.
Pedro Castro, 54, pleaded no contest to an open container charge while two charges against Onil Castro, 50, were dismissed.
"Ariel kept everyone at a distance," Tomba said.
One thing that remains a mystery, he said, is how the women were kept in the house so long.
"As far as the circumstances inside the home and the control he may have had over those girls ... I think that's going to take us a long time to figure that out," he said.
The women, now in their 20s and 30s, vanished separately between 2002 and 2004. At the time, they were 14, 16 and 20 years old.
At a news conference, authorities would not discuss the circumstances of their kidnapping and captivity.
City Councilman Brian Cummins earlier said: "We know that the victims have confirmed miscarriages, but with who, how many and what conditions we don't know."
"It sounds pretty gruesome," he added.
They never saw a chance to escape over the last 10 years until this week when Amanda Berry broke through a door and ran to freedom, alerting police who rescued the other two women while Castro was away from the house.
In newly released police audio tapes, a 911 dispatcher notifies officers on Monday that she's just spoken to a woman who "says her name is Amanda Berry and that she had been kidnapped 10 years ago."