Catholic residents of a Northeast Philadelphia neighborhood continue to mourn the loss of a church once known as “the heart of Tacony,” destroyed in a May 9 blaze that federal investigators have now ruled the result of arson.

Early that evening, fire ravaged the former St. Leo the Great Church at Keystone and Unruh Streets, gutting the structure. The blaze, which originated in the church, also severely damaged the former parish rectory, home to permanent diaconate candidate Pasqual Mota and his family, who had purchased the residence from the Philadelphia Archdiocese in 2016.

Philadelphia Fire Department Battalion Chief Christopher Beale told CatholicPhilly.com he believed the Mota house, which ignited from the church fire’s radiant heat, was “salvageable,” although “the whole third floor is a mess.”

The Philadelphia Fire Marshal’s Office and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) announced the fire had been deliberately set, although officials did not specify the details of their findings.

A $20,000 reward is being offered through those agencies for information on the person or persons responsible for the blaze.

The church fire was placed under control two hours after it broke out around 5:00pm by some 100 firefighters, with no injuries reported, said Philadelphia Fire Department Deputy Chief Vincent Mulray, who spoke to media on the scene.

Mulray said the blaze had resulted in “a total loss for the church,” with another fire official later noting vibrations from the nearby Amtrak train line would likely weaken the surviving structure.

Crews began demolishing St. Leo’s iconic bell tower the next day, and the remainder of the church is steadily being dismantled.

Later, the parishioners held a “spontaneous” rosary prayer service in Disston Park across the street from the ruins.