Puppeteer Kevin Clash is already facing similar allegations in three other cases.
Now, a new lawsuit accuses Clash of luring a teenage boy to New York from Miami in early 1996 for the purpose of sexual activity.
The alleged victim says he engaged in sexual activity with Clash in his New York on multiple occasions.
Clash has denied any wrongdoing in the first three cases.
He resigned from "Sesame Street" as Elmo's voice in early November.
But despite his stepping down, Clash's voice will be used for Elmo through 2014, as the next season of "Sesame Street" has already been filmed.