NATIONAL CITY, Calif. — National City police and other local authorities gathered Friday to announce that two people were arrested this week in the killings of 18-year-old Edwin Barrera and 16-year-old Gillian Aguilera, who were gunned down on East 17th Street after attending a Halloween party last October.

“Outside of this Halloween party, emerging criminal street gang members began hunting down what they considered to be rivals and in order to do that, to really make a name for themselves, they were going to commit murder. Victim Barrera was confronted by them, shot and killed — 16-year-old Gillian Aguilera was a bystander who was tragically also murdered,” said San Diego County District Attorney Summer Stephan.

Authorities say the suspects were 17 years old when they committed the killings. They’re in the juvenile court system now, but the district attorney is working to get them tried as adults.

Police say during that investigation, they discovered evidence of a bigger crime ring working in National City, Chula Vista and San Diego.

A joint investigation involving the San Diego County Violent Crimes Task Force has been ongoing since March, resulting in the arrests of nine people, including the shooting suspects.

“Over the course of the past three months, the joint investigation uncovered that a group of alleged gang members were working together to commit violent assaults, robberies, traffic drugs and commit weapons violations,” said National City Police Chief Jose Tellez.

About three weeks ago, National City police held a news conference asking for the public’s help in the Halloween party shooting and another attempted double-homicide in February, when a 20-year-old man and a 17-year-old boy were shot on East Plaza Boulevard as they walked to a restaurant.

Those victims are still recovering. Police have not made any arrests in that shooting.

“We believe, perhaps, these same individuals are all connected with that as well — the homicide and the attempted homicide — and so we still need the help of the public to come forward and give us information, if they have any,” said Tellez.