After months of searching for the most-wanted graffiti vandal in Greater Portland, South Portland police say they finally caught their man with a little help from reward money donated by an anonymous citizen.

Police on Friday announced they had tracked down the person responsible for countless appearances of the graffiti tag “BRO,” including several repetitions of it on the Interstate 295 sound barrier in South Portland along what is arguably the gateway to Greater Portland.

Police charged William H. O’Brien, 25 of 224 Pine Point Road in Scarborough with criminal mischief, issuing him a summons to appear in court May 21.

“It’s not art. It has an impact on our community that is just not healthy,” said Police Chief Edward Googins at a news conference Friday in announcing the charge.

Police executed a search warrant for O’Brien’s bedroom at his parent’s house on Pine Point Road on Thursday night. Inside they found a notebook with sketches of the graffiti tag “BRO,” said Detective David Stailing, one of the officers working on the case.

O’Brien then admitted to spraying the letters on the sound barrier as well as on other property in the city, Stailing said. O’Brien did not say what the significance of the letters were, Stailing said. He said it was the only tag sketched in O’Brien’s notebook.

Police issued O’Brien a summons rather than arrest him because he is charged with a misdemeanor, not a felony, the conduct did not happen in the presence of an officer, and he was cooperative, Googins said.

By the time he goes to court, O’Brien may face additional charges. He is linked to tagging on a sign on Broadway near the sound barrier, on the Wok Inn at 818 Main St. and on a sign on Maine Mall Road near Chipotle, Googins said.

Portland also is considering whether to bring charges for multiple appearances of the same tag on public and private property in that city.

“We do have some photographs of the ‘BRO’ tags in Portland and some complaints,” said Trish McAllister, Portland’s neighborhood prosecutor. “There’s no question we will assist the district attorney and South Portland police however we can, and ask for at the very least enhanced sentencing.”

The Maine Department of Transportation has been waiting for good weather to repaint the wall, said Ted Talbot, spokesman for the MDOT.

“The temperature has to be above 55 degrees for a few days in a row,” Talbot said. “We expect to start in a few weeks.”

The paint and labor are expected to cost $3,000 to $4,000. The state will seek restitution, as it has in past cases of graffiti vandalism, he said.

Googins said he receives many complaints about what he described as blight. “It just makes people feel unsafe,” he said.

That, and a sense of civic pride, were the motivation behind an anonymous donation of $5,000 to help find the person responsible for that graffiti and other tags around the city, Googins said. A committee comprised of an assistant Cumberland County district attorney, Portland’s neighborhood prosecutor and a South Portland police lieutenant has been set up to gauge the value of tips for determining how much of the reward money to pay out.

O’Brien was charged as a result of information provided to police by several people, including one who gave investigators O’Brien’s name, Googins said. He said he hoped some money would remain in the account to help with future cases.

“In all likelihood, had there not been an incentive of money, this could be an unsolved case,” Googins said.

The charges are not the first against O’Brien in South Portland.

In 2012 he was arrested on charges of burglary, aggravated criminal mischief and indecent conduct, according to court records. Police said he used a shoe to break several windows as he walked barefoot along South Portland’s greenbelt. He also broke into a car to steal change and was accused of exposing his genitals to people at Broadway Variety.

At the time, his mother blamed his erratic behavior on drug use.

He pleaded guilty to aggravated criminal mischief, a felony, and misdemeanor theft and was sentenced to 60 days in jail, all of it suspended, and told to pay $1,100 in restitution.

He also was charged with driving an unregistered vehicle in 2011. The officer who pulled him over was Stailing.

A woman who answered the telephone at O’Brien’s home said she did not want to comment.

David Hench can be contacted at 791-6327 or at:

dhench@mainetoday.com

Twitter: @Mainehenchman