According to the police, Kelly Mena, had slipped the bag of pot in a pink Minnie Mouse backpack, which the kid brought to her school in Harlem, the New York Post reported.
The law enforcement sources said that a teacher of the Early Life school discovered the drugs after she got a whiff of the stinky bud emanating from the bag.
School officials called the police and the parents of the child to the school.
The parents later showed up at the 32 precinct station house to talk to investigators, after which the police discovered that it was Mena who was responsible and arrested her.
Mena has been charged with criminal possession of marijuana and criminal sale of marijuana.