Suffolk County District Attorney Daniel F. Conley today announced the indictment of three men in connection with the fatal shooting of Paula Castillo at a party celebrating her 18th birthday.

The indictments charge RUBEN SANCHEZ (D.O.B. 9/6/90) of Hyde Park with second-degree murder for Castillo’s Sept. 20 homicide on Hillis Road.

The indictments also charge MIGUEL VASQUEZ (D.O.B. 5/5/91) of Boston’s South End with assault by means of a dangerous weapon and ANDREAS BREA (D.O.B. 1/25/90) of Roxbury with being an accessory after the fact to assault by means of a dangerous weapon.

All three men are additionally charged with unlawful possession of a firearm, unlawful possession of ammunition, and unlawful possession of a loaded firearm for possessing the handgun that allegedly killed Castillo.

Evidence developed in the course of the two-month grand jury investigation suggests that Sanchez and his cohorts arrived at Castillo’s birthday party and became engaged in a verbal altercation with others present. Another partygoer asked the three men to leave.

The three men did leave the building but continued to exchange words with other people outside. At about 2:30 a.m., Castillo leaned out a window and addressed them. With Vasquez allegedly urging him to display the weapon and “show them what you got,” Sanchez allegedly fired multiple rounds from the handgun. One of those shots struck Castillo in the neck. She died within minutes.

Brea allegedly drove Sanchez and Vasquez from the scene. A description of their red Honda Civic was relayed to Boston Police, who stopped it and brought the occupants in for questioning after the shooting. A search warrant later executed on the vehicle led to the recovery of a firearm.

Sanchez is represented by attorney Ronald Brandt. He, Vasquez, and Brea are expected to be arraigned in Suffolk Superior Court on Dec. 14.