Police are investigating what led to the evacuation of a popular convention in Morris County Saturday.

Parsippany police say it started with a report of a gas leak at the Hilton Hotel.

It happened during the Chiller Theater convention with about 3,000 guests there at the time.

Police evacuated the area around the leak when they got a call that someone called in a bomb threat.

At that point, the entire hotel was evacuated.

"The first report is that it was a gas leak and then we heard reports that it was suspicious package. And the rule of thumb is you get away from the windows so shards of glass can't harm you if there's an explosion and there were people milling around the front of the building," says Glenn Manjorin, of Ringwood.

Guests were allowed back in just after 6 p.m.

Chiller Theater will continue Sunday.