Guards at the Metropolitan Correctional Center found the bag of marijuana in a bag belonging to attorney Seth Ginsberg, the New York Daily News reported.
Ginsberg planned to visit a reputed Gambino soldier, and was asked to open his bag before entering the facility, the report said.
"I had no idea there was anything illegal in my bag. I had no intention of bringing anything illegal to my client, nor would he ever ask or want me to," Ginsberg said.
Ginsberg's brother has said the pot belonged to him, and Ginsberg's colleagues said he would never participate in any smuggling missions.
"Anyone who knows Seth knows this is some crazy happenstance," said lawyer Charles Carnesi.
Carnesi said Ginsberg's younger brother submitted a sworn affidavit acknowledging the marijuana bag was his.
The incident happened on Oct. 12, as Ginsberg visited the lockup to see Thomas Orefice, who is accused of recruiting girls for an underage prostitution ring, the report said.
Ginsberg was refused entrance, but was allowed to leave the screening area. He returned a short time later without the marijuana, but was again refused permission to enter. He was not arrested.
A corrections officer later found what was believed to be the same bag of marijuana in a nearby trashcan, the report said.