The South Plainfield man arrested on charges of possessing homemade explosive devices that police said were found at a bar, at his home and at another location near his home could soon face additional charges.

Thomas Kaiser remains in the Monmouth County jail on Tuesday after being charged on Monday with possession of a destructive device for an unlawful purpose and possessing a destructive device. The South Plainfield Labor Day Parade, which Gov. Phil Murphy was to attend, was cancelled because the explosives “could have been quite dangerous to anyone in the community," said Monmouth County Prosecutor Chris Gramiccioni, whose office is prosecuting the case because it began in Sea Bright.

The investigation began after a suspicious package was found at Donovan’s Reef, where the Guns 4 Hire Acoustic Trio had been performing Saturday night.

The group posted a statement on its Facebook page indicating the package was actually a fireworks gift that had been dropped off by a longtime fan who had made an “error in judgment.” But Gramiccioni said the devices were not fireworks.

“We would allege they are very rudimentary explosive devices, similar to the size of a cut-up coffee can that had fuses as well as gunpowder in and around it," he said.

He would not say how many devices were found, or where exactly they were discovered but stressed that they did in fact pose a danger to the public.

While fireworks also contain gunpowder, the type of devices discovered “can create a much greater risk to the general public than a firework, which is meant to be launched into the sky," Gramiccioni said.

A half-mile sweep of the area around Kaiser’s house was conducted by the State Police bomb unit working with county and local police.

Kaiser is scheduled to appear at a detention hearing on Friday.

You can contact reporter David Matthau at David.Matthau@townsquaremedia.com