After almost a week, Castillo's body was finally found a little more than a mile from where he first disappeared.
"He's very sad. He's a man. The feeling of a father who lost his son," said Oscar Macalnda, a family friend.
Surrounded by friends and relatives, the boy's parents positively identified the remains as those of their son Sunday afternoon at the Cook County Medical Examiner's office.
The discovery was made just before 11 a.m. Sunday in the river behind a river park water treatment facility, downstream from the 5100-block of North Ridgeway where the elementary school honor student fell into the river last Sunday.
Searchers spotted the boy's body after police cadavers dogs detected a scent in the area.
"It was just north of Lawrence Avenue on the east side of the river. It was just below the water line. It was barely visible. They saw it floating in the water," said Cmdr. Mike Mealer o of the Chicago Police Department.
Cashmere Castillo went missing after relatives say he jumped a fence and fell into the river during a game of tag at the park. His 13-year-old brother yelled for help, and a passerby then jumped into the water to try to save the child, but the current swept the boy away.
During a Little League game Saturday, six days later, the 8-year-old's teammates and coaches wore shirts with his initials on them.
The children were reportedly struggling with the loss, but their coach said playing baseball together helped them honor Castillo's memory.
The weeklong search had been frustrating for divers who wanted to help Castillo's family.
"Really want to find him," said Officer Jack Hayes of the Marine Unit Saturday. "I want to provide the father, the entire family with some closure. I can't even imagine what it would be like. So, I and all the Marine Unit officers want to find the victim."
The boy's father, Willy, donned scuba gear and dove into the Chicago River Saturday morning to search himself before police arrived that day.
Sunday, members of the family's Albany Park community --who took part in a prayer vigil-- said feelings of sorrow over the loss of Cashmere had become relief that the ordeal was finally over for his family.
"From the very beginning they call off the search, my boy is gone. But I was hoping we would find his body, which we did. That's all I was hoping, give me my closure, for my family, for my kids," said father Willy Castillo.
The family thanked the rescuers who worked so hard to find the child.
An autopsy on Cashmere Castillo is scheduled for Monday.