A Cumberland County grand jury has indicted a Scarborough man on charges of aggravated criminal mischief, a felony, in connection with the letters “Bro” that were painted on the sound wall along Interstate 295 in South Portland.

The grand jury indictment of William H. O’Brien, 25, of 224 Pine Point Road, accuses him of painting the wall between November 2013 and January 2014. Police say O’Brien not only spray painted large black balloon letters on the sound wall at a prime entrance to Greater Portland but also tagged other pieces of public and private property.

Aggravated criminal mischief is a felony if the person responsible causes more than $2,000 in damage. Early estimates of the cost of repainting the sound wall were $3,000 to $4,000. The state planned to seek restitution from O’Brien.

Police said they were able to find O’Brien based on tips that were motivated by an offer of reward money. The reward money had been posted by a concerned resident who wanted to remain anonymous. Police ultimately paid out $1,000 for the information leading to O’Brien.