"Now that I think of it, he didn't want nobody back there."
Neighbor: 'Breaks my heart that I could have done anything'
While some characterized Castro as upbeat and outgoing, his uncle described him as withdrawn.
The uncle, Julio Castro, said Ariel isolated himself from his extended family after his father died in 2004. The uncle lives just half a block from the house where the women were rescued but had not spoken to Ariel in years.
On Monday, he saw a commotion down the street and walked over there, where police told him about the rescue.
His first thought was that it was impossible that his nephew had anything to do with it. But, Julio Castro told CNN en Español, "perhaps, he was the type of person who was living two lives."
Marti also suspects, now, that there may have been more to Ariel Castro than what he'd believed.
As someone with grandchildren himself, who prided himself in being a good neighbor who watched out for others, Marti said that it hurts that he didn't notice the signs and act to help those three young women.
One of them, Georgina DeJesus, is the daughter of a friend he's known since the 1970s. For years, Marti said he prayed for her -- and finally his prayers were answered, just not how he ever envisioned.
"It breaks my heart that I couldn't have done anything for them girls," Marti said.