Police records show Jason James Murphy was convicted of kidnapping and molesting an eight-year-old boy in Washington state 15 years ago.
Abrams recently learned the 35 year old is the same person his casting directors hired as an assistant to the kids on the set.
He tells the Los Angeles Times newspaper, "It's shocking and it's devastating, not just as a filmmaker but as a father and someone who is entrusted to make sure that everyone I work with, especially children, are safe. To think that someone like this was among us is unthinkable."
Murphy, who has been using the name Jason James while doing business in Hollywood in recent years, has also worked with young stars on the sets of Bad News Bears, The School of Rock, Cheaper by the Dozen 2 and the much-anticipated new movie The Three Stooges.
The Los Angeles Times reports Murphy served five years in prison and underwent counselling as a sex offender. In 2005 he moved to California and registered as a sex offender, but then went to work as Jason James, thus hiding his true identity.
There are no known complaints that Murphy acted inappropriately with any minor in his casting business, but it appears he has broken a number of state laws, which dictate he must notify the authorities to any name changes, nicknames or pseudonyms, and he cannot work directly with children.
Abrams insists there was nothing to suggest the man he knew as Jason James was a child sex offender.
He adds, "(We) had absolutely no knowledge of his real name, nor of his status. He applied for the job under an alias."
Super 8's casting directors, April Webster and Alyssa Weisberg, insist they were unaware of Murphy's background when they hired him as an assistant, but they tell the publication he was never alone with children while in their offices.