NORTH ANDOVER — Twenty-five years ago, Lawrence was burning.
During the first five months of 1992, more than 130 fires erupted in the city. Firefighters were exhausted, and some of the investigators looking into the arson cases were reassigned. Authorities convened a task force and recruited new detectives.
Among them was Paul Zipper, a State Police trooper who specialized in child sex abuse cases for the Essex district attorney’s office and was working on a doctorate in sociology. He knew nothing about fire investigation, but was known as a skillful interrogator.
On Zipper’s first day on the job, task force leader Robert Corry sent him to investigate a building fire. Three hours later, Zipper returned and declared he knew who set the blaze.
“I said to him, ‘Paint me a picture,’ ” said Corry, a retired State Police detective lieutenant. “He started telling me the evidence they had put together. He had gotten so much information and so many statements. I’m looking at him and it dawned on me: I have a master detective here.”
A quarter of a century after Lawrence’s arson crisis launched Zipper’s career as a fire investigator, he is now a detective lieutenant who leads the State Police Fire and Explosion Investigation Unit, which is assigned to the state fire marshal’s office.
Some of his notable investigations are the 1995 Malden Mills fire in Lawrence; the prosecution of Anthony Baye, who admitted to a deadly arson spree in Northampton in 2009, and a 1989 case that changed the way police interrogate juveniles after a 12-year-old boy was accused of setting a blaze that killed a firefighter.
It’s a role Zipper, 56, never envisioned when he started in Lawrence.
“I wanted nothing to do with fire investigation,” Zipper said in an interview at Merrimack College, where he teaches part time. “I liked a nice white-collar job. Suit and tie.”
At 6 feet 1 inch, Zipper has a larger than life physical presence animated by his jovial demeanor. He grew up in Peabody and both his parents worked for publisher Houghton Mifflin in Burlington. Zipper’s mother was a key puncher and his father was a programmer.
For his 5th birthday, Zipper’s aunt gave him a book: “I want to be a policeman.” His future was set.
He graduated from Westfield State University and earned a master’s degree at American University in Washington, D.C.
Zipper returned to Massachusetts, where he enrolled in a sociology doctorate program at Northeastern University on a scholarship while working security at the Royal Sonesta in Cambridge. He took the State Police exam in 1985 and enrolled in the academy the following year.
Zipper’s assignment in Lawrence was scheduled to last three months, but on his last day, five fires were set within an hour. A few days later, a massive blaze on Chandler Street flattened a 16-unit apartment building and two other residences.
Zipper’s tour was extended another 30 days, but he decided to stay and work for Corry, who became his mentor. Zipper’s youngest son is named after Corry.
“I started enjoying what I was doing. I was having a lot of success arresting people who set fires,” Zipper said. “I finally said, ‘I give up. I want to work here for you.’ ”
Investigators who have worked with Zipper said he makes friends easily, helping him crack cases.
“His strength is dealing and working with people and befriending them,” said State Police Sergeant Paul Horgan, who is assigned to the bomb squad. “He also had and still does have a great talent for getting people to talk to him and suspects eventually wanting to confess to him.”
The ways Zipper has solved some cases are the stuff of lore.
After a fire destroyed three buildings in Lawrence, Zipper played pick-up basketball games at a nearby court until neighborhood teenagers revealed who set the blaze, Corry said.
The 17-year-old suspect confessed to starting the fire to impress a girl, Zipper said.
In another case, Horgan and retired Revere fire chief Gene Doherty called Zipper to interview a man they suspected of setting fire to his neighbor’s fence.
Investigators said the suspect was incorrigible, but he also claimed to be religious so Zipper came to the interview wearing a suit and carrying a Bible, Doherty said.
To prepare, Zipper said he researched biblical references to fire.
“I’d read him a paragraph about fire in the Bible. I did that game with him,” Zipper said. “I said, ‘I know you did this.’ ”
The suspect confessed.
“It was a classic,” Doherty recalled, laughing.
While Zipper investigated fires for his day job, he chipped away at his doctorate by taking one course every semester. It took him 15 years to graduate.
In 2012, Zipper passed the lieutenant’s test and was tapped to run the Newbury barracks. The facility is near the former Adventureland, a theme park that had its heyday in the 1950s.
Zipper said he embraced this quirky history by researching the park and having T-shirts and coffee mugs made for his troopers featuring the State Police bulldog mascot and the park name.
Nearly three years ago, Zipper returned to the state fire marshal’s office to lead the team of fire and explosives investigators.
“He was definitely on the short list very early on,” said state Fire Marshal Peter J. Ostroskey. “He’s really a great leader.”
Zipper leads the unit full time while teaching at night at Merrimack College.
For his youth crime and deviance class, Zipper blends reading assignments with stories from his time in the field.
“While we’re reading the different books, he can tell us, ‘This is what you’ll see when you’re investigating these things,’ ” said Aleksa Thomas, 19, a sophomore from Boxborough. “And he asks us about our opinions too. It’s not just about his opinion. He wants to know what we found to be interesting.”
Zipper said the key is being good to others.
“I truly believe that people want to do the right thing. They really do. But they need to feel like they’re doing the right thing, for the right person,” he said. “I will take that to my grave.”Laura Crimaldi can be reached at email@example.com. Follow her on Twitter @lauracrimaldi.