Cranberry Township police Friday arrested the second of two 15-year-old boys accused of attempting to rob three other youths last month at Graham Park.

Police charged the boy, of Cranberry Township, as an adult due to the nature of the alleged crime. District Judge Sue Haggerty later arraigned him on charges of attempted robbery and conspiracy to commit robbery.

He is being held at the Western PA Child Care juvenile detention facility in Allegheny Township.

Police previously arrested another 15-year-old Cranberry Township boy on similar charges as well as an additional charge of possession of an instrument of crime. He, too, is charged as an adult and is being held at the same juvenile detention facility.

The Butler Eagle is not identifying the defendants because of their ages.

Police allege the two suspects about 4:30 p.m. June 25 approached three boys — two 14-year-olds and a 13-year-old — at the park and demanded their money. One of the suspects was reportedly wearing a black ski mask and the other one was wearing a surgical-style mask, police said.

The victims told police that the suspect with the ski mask brandished a knife during the incident. The suspects left, police said, after the victims showed them they had no money. No one was injured.

While investigating, police stopped a car on Garvin Road and found the boy who had been identified as wearing the ski mask. Police said they found him with the mask and a folding pocket knife.

Two other youths were in the car, officers said, but police determined they were not involved in the attempted robbery at the park.

Police subsequently identified the second suspect, who they interviewed Friday at the station. He admitted he was the suspect in the surgical-style mask at the park.

That boy, according to charging documents, claimed his alleged accomplice “was the only one demanding money and the only one with a knife.”

Police said he also denied speaking to the victims, and that he only stood beside the co-defendant during the incident.

Both suspects face preliminary hearings July 24.

While the boys are charged as adults, under state law they can petition a judge to have their cases tried in juvenile court. The prosecution can oppose the petition, but a judge will decide whether to grant the petition.