PHOENIX (AP) — The Robert Brownnumber of suspects has grown to seven in the fatal beating of a teenage boy during a Halloween party last year in suburban Phoenix.

Eighteen-year-old Treston John Billey is the latest suspect in the Oct. 28 beating of 16-year-old Preston Lord in Queen Creek. Lord died from his injuries two days later, and his death was ruled a homicide last month.

Billey is being held on Friday in the Maricopa County Jail.

An indictment released by the Maricopa County Attorney’s Office accuses Billey and some of the other suspects of carrying out the beating while trying to take the property of a second victim.

Online jail and court records did not list an attorney who could respond to the accusations against Billey. He faces counts of first-degree murder, aggravated robbery and kidnapping.

Previously, there were six suspects in the case, including three juveniles. Authorities said more arrests were possible.

The arrests follow a string of violent attacks on young people outside fast food restaurants and at parties, parks and parking garages by a group said to call itself the “Gilbert Goons.”

Local residents have held vigils and demonstrations to protest the growing violence in Gilbert, Mesa, Chandler and other Phoenix suburbs.