LAWRENCE - Investigators have ruled out arson as the cause of a fire at Turn Hall, instead saying teenagers playing with a lighter accidentally ignited the blaze that gutted the cavernous, 141-year-old building.

The four boys range in age from 13 to 15 and are students at one of the city's middle schools, police Chief John Romero said yesterday.

Meanwhile, ownership of the Park Street building appears to be muddled leaving the fate of the property uncertain.

The boys were questioned by police after a schoolyard argument over who had caused the fire Sunday night, and school administrators turned the boys over to police and fire investigators.

"These are not bad kids," fire chief Peter Takvorian said. "It was mischievous."

"It was kids being kids," he said. "We have a source of ignition, cause and origin."

Romero said the boys had been in the building before and were there again Sunday, playing with a lighter one had brought from home.

"They had lit up some newspapers and some other stuff, some toilet paper, and were horsing around," Romero said. "They thought they had put it all out."

"They were in there looking for spirits and ghosts, as kids will do in an abandoned house," Romero said. Police and firefighters will discuss the blaze with prosecutors, but do not know yet if the boys will face criminal charges.

Fire investigators are now certain the four-alarm blaze, which gutted the 21/2 story brick building, was not the result of arson, Takvorian said.

The large brick building at 42-44 Park St., once a social club and athletic club and more recently a church, is under fire watch until a decision can be made on whether to tear it down. Takvorian thinks demolition will be necessary.

Most distressing though, Takvorian said, is knowing that the blaze could have been avoided if the building had been properly boarded up.

"If these kids couldn't get in there, that wouldn't have happened," he said. There are about 250 abandoned buildings in the city and firefighters will be making sure they are properly secured, Takvorian said, pledging prosecution of lazy landowners.

But who owns Turn Hall is uncertain right now.

For years, the property has been caught in a crossfire of competing real estate interests.

Going back as far as June 2002, Mental Health Resources Plus Inc., of Lawrence, which operates housing for people with mental disabilities, had an agreement to buy the property from the owners, the Society for the Latin Mass. The local social services group had hoped to erect housing for their clients, but those plans were dropped after Lowell developer Christopher Cox sought approval for his own project on the site - 24 condominiums along with low-income housing.

However, Cox's project was rejected by the Planning Board in May 2003 after then-City Councilor Michael Sweeney challenged whether Cox actually owned the property. City Councilor Patrick Blanchette also challenged the project, saying Cox was putting too many units on the 1.4-acre site. Cox could not be reached for comment on this story, but said during the May 2003 hearing that he did own the site.

More recently, Jay Berglund, a developer from Groton, Mass., secured approval from the Planning Board last summer to raze the building and erect 12, single-family detached condos on the site. City Planner Michael Sweeney said Berglund was given approval for his project in July 2007. But it's unclear whether Berglund ever owned the property.

According to the Northern Essex County Registry of Deeds, the property was sold in the past month to Christian Methodist Realty Trust, a local group that intends to build a church on the site, according to Dan McCarthy of the Lawrence Planning Department.

McCarthy said he found out about those plans last week from a local attorney representing a builder doing work for the church.

Berglund said he plans on challenging the sale of the property to the church organization.

"I'm interested in putting condos on that site after the fire investigation is over," he said.

Hector Mateo, listed by the Registry of Deeds as being with Christian Methodist Realty Trust, could not be reached for comment.