East Palo Alto police have identified Julian Rico Santana as the person who allegedly shot and killed two men during a Halloween party on Oct. 14, 2018.

Authorities are seeking the public's help in locating Santana for the deaths of Eduardo Alvarado Sandoval, a 22-year-old Stockton resident, and Mario Andres Vidalesmendez, 23, of East Palo Alto.

On Tuesday, the Police Department announced a $20,000 reward in partnership with Palo Alto-based nonprofit Mothers Against Murder for information leading to the arrest and conviction of the suspect in the double homicide.

Santana, 20, of East Palo Alto, came uninvited to the party, which was held outside the rear of a business in the 2500 block of Pulgas Avenue near Bay Road, police said. He allegedly became involved in a dispute that incited a physical altercation and shot four people before he fled the scene, according to police.

Police received a ShotSpotter activation at about 2:44 a.m. and 911 calls reporting the shooting. Officers found four people with gunshot wounds. Sandoval and Vidalesmendez died at the scene and the other two were transported by emergency response crews to nearby hospitals with life-threatening injuries.

Santana is described as being 5 feet and 10 inches tall, weighing 240 pounds and having black hair and brown eyes. People who see Santana are warned not to confront him but to call the police and wait for them to arrive, police said.

The $20,000 reward is an increase from a $5,000 reward Mothers Against Murder previously offered to find the shooter in April 2019.

"He's nowhere to be found for two years now, leaving families of his violence in a lot of pain and desperate for justice," Margaret Petros, executive director of Mothers Against Murder, said in a separate statement.

"Remember, the milestone that the City of EPA had reached of zero murders in 2017 and through 2018, until Julian, a young man with a gun brought so much damage and pain to four young men and ruined his life in (a) few moments of anger."

Veronica Sandoval, the mother of Eduardo Sandoval, previously asked for the community to help find her son's alleged killer. In a Dec. 1 video, she begged for the public's help.

"Oct. 14, 2018, the last day I saw my living son. That day our lives changed forever, as a mother, every member of my family and anyone else's hearts that in some way were touched by my son.

Based in Palo Alto, Mothers Against Murder advocates for families of murder victims and works to ensure the rights of homicide victims within the criminal justice system since 2003.

Anyone who might have witnessed the shootings or has any knowledge of this incident is urged to contact the East Palo Alto Police Department by calling Detective Aleyda Romero at 650-853-7249. Anonymous tips can be made by email to [email protected] or text or voicemail to 650-409-6792.