Beginning July 1, Ohio will join a handful of states requiring convicted arsonists to register their addresses with county sheriffs.

Beginning July 1, Ohio will join a handful of states requiring convicted arsonists to register their addresses with county sheriffs.

The resulting database will be of great value if a rash of blazes breaks out in a neighborhood after someone who sets fires moves in, said James Patterson, an investigator with the Fire and Bomb Investigation Unit of the Columbus Division of Fire.

Patterson, who covers the Northland area but was previously assigned to northwest Columbus, was the guest speaker last week at a meeting of Northland Block Watch coordinators.

The arson database will be similar to the registration requirement for sex offenders, but without restrictions regarding how close to schools a convicted arsonist lives, Patterson said.

Ohio will join the few states that require convicted arsonists to register with authorities, in the hopes that it will help solve more cases, deter repeat offenses and prevent deaths and property damage, according to the website of Insurance Journal.

The new law will require people convicted of arson-related offenses to register annually with their local sheriffs for at least 10 years after they're released from prison or, if not imprisoned, sentenced.

The requirement applies regardless of whether the offenders were convicted in Ohio or elsewhere, but it doesn't cover those who have already completed their sentences.

Patterson, who grew up in the Northland area and has been with the Columbus Division of Fire for 21 years, said the Fire and Bomb Investigation Unit has seven structure investigators and two employees who work automobile fires only.

"Auto fires in Columbus are out of control," Patterson told the Block Watch leaders.

In 2012, the unit investigated 960 fire scenes, Patterson said. These fires involved six fatalities, he said. Investigators filed charges against 67 adults and referred 76 juvenile offenders to diversion programs.

In part, Patterson said, so many more scenes of possible arson are checked out than lead to arrests because, often, vacant houses are torched.

"There are no witnesses, none at all," he said.

People set fires, he said, for several reasons:

* For purposes of committing fraud.

* To conceal a crime.

* As acts of terrorism.

* Revenge.

* To experience sexual gratification.

"It's surprising how many of them do it for sexual gratification," Patterson said.

He referred to a case of a man who was 19 when he made his first false-alarm call regarding a fire, because of the sexual thrill he got at the sight of the trucks arriving with lights and sirens going. The man was finally caught, still phoning in false alarms, at the age of 62, Patterson said.

He also enlightened his audience about the dangers of so-called "MacGyver bombs." Named for the extraordinarily resourceful title character of a 1987-92 action-adventure TV series, the homemade chemical devices can be created in plastic bottles using household products.

Juveniles sometimes make them as a prank, Patterson said, but they're no joke.

"They'll blow up a mailbox to pieces. It will take your fingers off," he said.

Almost as bad, Patterson said, are unexploded devices containing acids that can harm people who innocently handle them.

During his stint assigned to northwest Columbus, Patterson said he apprehended between 25 and 30 juveniles for making MacGyver bombs.