A young volunteer firefighter, already accused of setting fire to Delaware County homes, now faces child-rape charges amid allegations he groomed then raped more than a dozen children over a 2-year period.

The Delaware County District Attorney's Officer announced an additional 161 counts -- including child rape and luring -- against John Corcoran IV Friday.

Corcoran, 20, was already set to go on trial next month on 78 counts including arson, according to court records.

The child-rape charges came after investigators uncovered allegations that Corcoran lured and groomed 14 children, boys and girls ages 8 to 14, and repeatedly sexually assaulted the children over a two-year period.

District Attorney Jack Whelan said one of Corcoran's victims including a girl with mental disabilities who he filmed.

Many of the attacks happened in the showers at the Ridley YMCA and at the Lower Swedish Cabin in Upper Darby and that Corcoran would use porn to lure children, said Whelan.

Investigators said Corcoran preyed on loners or isolated kids and often lured in the boy's using pornography.

Police uncovered the alleged assaults after a mother told them her child received porn from Corcoran, said Whelan.

Some of the attacks even occurred while Corcoran was out on bail for the earlier arson charges.

Authorities became aware of Corcoran after crews were called called to a house fire on Delmar Drive in Folcroft, Pennsylvania -- right across the street from the firehouse -- back in July. When they arrived they found a vacant home in the woods with flames coming through the roof.

Investigators deemed the fire suspicious since the home had been vacant for several years and didn’t have any utilities inside. The fire was later ruled arson.

About two weeks later, investigators interviewed Corcoran, who volunteered with Glenolden's Goodwill Fire Department. During the interview, Corcoran allegedly admitted to helping a 17-year-old Tinicum Township boy set fire to the home. Police said Corcoran was driving the teen around the night of July 20 when they decided to light the Delmar Drive home on fire.

“I won’t get caught, I’m a ninja,” the teen allegedly told Corcoran.

Investigators said Corcoran dropped the teen off at the home and the boy used a lighter to light paper on fire in the bathroom. Corcoran later picked the teen up and the two fled the scene, according to investigators.

Corcoran also allegedly admitted to helping the teen light two other homes on fire in the Briarcliff section of Darby Township. Corcoran also later responded to both of those fires and helped put them out, according to investigators.

Both Corcoran and the teen were arrested and charged with arson.

Corcoran was out on bail for the arson charges when he was arrested last month on the child-rape charges, said prosecutors.

Investigators know of the 14 victims but said that local auhotiries along with the FBI were looking into the posiblity that more children could have been victimized.

His lawyer in that did not immediately return a message for comment.