A Jet Blue flight took off from Boston Friday night and then landed in Newark, New Jersey, where the plane's cleaning crew found a stun gun.

The Striker 1800 was found in a seat back pocket and was turned over to authorities. Now the investigation is turning to how a stun gun made its way onto a plane and who brought it on, something investigators may never know.

Jet Blue passengers are uneasy with the stunning discovery, and rightfully so. Fred Hevalt, an airline security expert who produced the documentary "Please Remove Your Shoes," however, says that it's possible to get all sorts of things through airport security and people shouldn't be all that surprised now.

TSA officials declined to be interviewed, but released a statement saying, "TSA employs multiple layers of security to minimize risk, deter future attacks and protect the traveling public."

The particular stun gun sells for around $20 on the Internet, but in Massachusetts, it is illegal for private citizens to possess a stun gun. The stun gun, however, could have made its way onto the flight in a number of cities as the plane made several other stops.