The Board of Supervisors has offered a reward of $10,000 in the shooting death of a 26-year-old army veteran killed on the doorstep of his cousin’s birthday party in Lancaster.

Supervisor Kathryn Barger called for a reward for information on the whereabouts of a suspect in the fatal shooting of U.S. Army veteran Ismael Zabala.

Zabala and his brother, Charlie, were reportedly attending a cousin’s Dec. 20 birthday party in the 400 block of West Avenue J-12. Ismael was fatally shot while standing at the front door of the Lancaster home at about 2:30 a.m.

Charlie was also struck by gunfire, but survived.

Zabala had been recently honorably discharged from the U.S. Army, and Barger said his family was “distraught by this senseless tragedy.’’

Investigators identified Oscar Palazuelos and Ervin Alvarez as being involved in the killing. Warrants were issued, Alvarez was subsequently arrested, and Palazuelos remains at large, according to Barger.

Anyone with any information on the shooting is encouraged to call the Sheriff’s Homicide Bureau or Crime Stoppers, or visit http://lacrimestoppers.org.