Preston — It was a pyrotechnics display impressive enough to rival a Hollywood action flick and rattle a few windows at the former Norwich Hospital property.

FBI bomb technicians on Wednesday used everything from household chemicals to full sticks of dynamite to demonstrate an array of explosions — creating a wall of fire, sending a burning tire 100 feet into the air and rattling observers with a concussive impact.

They even blew up a Perdue oven roaster chicken to demonstrate the impact of an explosion on the human body.

The demonstration was day three of a five-day post-blast bomb school hosted by the FBI's New Haven division and Connecticut State Police Emergency Services Unit.

More than 60 local, state and federal law enforcement personnel, including a Norwich police officer, are learning to investigate crime scenes through the recovery and reconstruction of bomb components, crime scene analysis, interviews and other techniques, said FBI Special Agent Sam DiPasquale, a bomb technician coordinator.

"There's a big difference between talking about it in a classroom and actually seeing and hearing it," DiPasquale said.

Course participants on Wednesday picked through the debris left by the explosions and later this week were expected to develop probable cause for an arrest after visiting one of five different rooms in one of the sprawling buildings on site. Bombs were detonated inside the rooms, creating a post-blast scene ready for investigation.

"It's the real deal," DiPasquale said. "Investigation should lead to an arrest and prosecution."

FBI Special Agent Tim Petrousky, a bomb technician and instructor from Baltimore, narrated the day's demonstration. He showed how, with the right mixture, commonly available items such as brake fluid, anti-freeze or ammonia could be used to make an improvised incendiary device.

Preston Fire Marshal Thomas Casey, who completed the course five years ago, said the skills necessary to identify bomb components, or recognize when a certain chemical was used, are unfortunately needed "in the world we live in today."

Norwich Police Officer Robert Smith, a member of the city's arson task force, said the training will be useful in future investigations — especially the ability to identify certain bomb-making materials or chemicals used to start a fire.

"It's absolutely valuable, probably one of the best instructional classes I've been to in a long time," Smith said.

With the April bombing in Boston still fresh on their minds, members of the Hartford Marathon Foundation took the opportunity to watch the explosions and planned to pass along information to members of their security team.

g.smith@theday.com