The number of suspects has grown to 7 in the fatal beating of a teen at an Arizona Halloween party

PHOENIX — The number of suspects has grown to seven following the fatal beating of a teenage boy during a Halloween party in suburban Phoenix last year.

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

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

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

Online jail and court records did not list an attorney who could comment on the charges against Billey. He faces charges of first-degree murder, aggravated robbery and kidnapping.

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

The arrests follow a series of violent attacks on young people outside fast food restaurants and at parties, parks and car parks by a group calling themselves the ‘Gilbert Goons’.

Local residents have held vigils and rallies to protest rising violence in Gilbert, Mesa, Chandler and other Phoenix suburbs.