SoHo, a lower Manhattan neighborhood now known for its boutique shops, art galleries and loft apartments, at the time was considered a grittier locale, where abandoned storefronts dotted the city streets.
Sweeney said he remembers the initial investigation into Etan's disappearance when police first knocked on his door in search of clues.
"That's odd, isn't it," he said, referring to the fact that 33 years later, police are again in his neighborhood searching for the boy.
On the day of his disappearance, Etan's mother, Julie Patz, learned after her son failed to return home from school that he hadn't been in classes that day. She called the school, then called the homes of all his friends. When she found no one who had seen her son, she called police and filed a missing person report.
By evening, more than 100 police officers and searchers had gathered with bloodhounds. The search continued for weeks, but no clues to Etan's whereabouts were found.
The boy's disappearance was thought to raise awareness of child abductions and led to new ways to search for missing children.
President Ronald Reagan named May 25, the day Etan went missing, National Missing Children's Day.