Hundreds of professional-grade fireworks mortars are missing from an abandoned semitrailer that was burglarized in Woodridge, authorities said Wednesday.

Investigators still are trying to track down both the person who abandoned the trailer and whoever broke into it several weeks ago.

It appears high school students took some of the potentially dangerous fireworks, police said. They may have come upon the trailer after the initial burglary.

Sgt. Jim Ruff, who heads the DuPage County Sheriff's Hazardous Device Unit, said Wednesday his team recovered and disposed of between 8,000 and 10,000 of the mortars when they were called to the scene in late May. However, they also found scores of empty containers that could have held hundreds of the fireworks that are used in commercial displays.

Days after being called to the trailer, Ruff said his unit was dispatched to a residence in a neighboring community where a high school boy had stashed more than 100 of the mortars in his closet. Authorities were alerted by the boy's father.

Ruff said the boy told investigators high school students had been raiding the trailer for weeks. The boy had been riding his bicycle to the trailer and stuffing his backpack with the mortars, Ruff said.

The mortars are equipped with a "quick-match fuse," Ruff said. Even though the fuses may be 15 feet to 20 feet long, if lit manually they can detonate before the user gets a safe distance away. Pieces inside the mortars can pierce the human body, Ruff said.

"If I was holding it under my arm and lit the fuse, I'd be dead and anyone close enough to hear me talking would be at least badly injured," Ruff said.

One of the mortars could burn a car to its steel frame if it were detonated inside the vehicle, he said.

Ruff said the mortars did not come with instructions or proper launching equipment.

The ball-shaped mortars are covered in brown and white paper, Woodridge police said.

Woodridge Deputy Chief Gina Grady said the trailer was found on a residential property. The property owner is licensed to have fireworks, but contends he was unaware of the contents of the trailer.

Grady said the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives is handling the investigation into the fireworks' origins.