EAST PALO ALTO, Calif. -- East Palo Alto police are investigating a homicide that happened Saturday night following an argument between two men at a child's birthday party.

Officers responded to a report of gunfire at about 11 p.m. from people near the intersection of Bell Street and University Avenue.

The officers spotted a white van that was stopped and blocking the westbound lanes of University Avenue. Upon closer inspection, officers discovered that the driver was slumped over and suffering from an apparent gunshot wound.

The driver, East Palo Alto resident Eduardo Bustos Martinez, was pronounced dead in the car by Menlo Park fire and medical personnel, according to police.

A preliminary investigation into the fatal shooting led to the discovery of other passengers in the van, including two men and two toddlers.

The toddlers were not injured, but the front-seat passenger, East Palo Alto resident Omar Camarena-Luna, sustained multiple gunshot wounds to his lower back and was transported to a nearby hospital. He was in stable condition, according to police.

Officers also discovered that prior to the shooting, Camarena-Luna and Martinez had attended a child's birthday party at the senior center on Bell Street where Camarena-Luna had been involved in an argument with another man.

Attendees at the party stepped in to diffuse the argument and Camarena-Luna and Martinez decided to leave shortly thereafter in a white van with one other man and two toddlers, according to police.

As Martinez was exiting the parking lot of the senior center, an unknown suspect fired at the van multiple times and struck Martinez and Camarena-Luna. A preliminary investigation revealed that it is unlikely that Martinez was the intended target of the shooting.

The motive behind the shooting is under investigation by detectives from the criminal investigations division of the East Palo Alto Police Department.

East Palo Alto police are encouraging anyone who may have witnessed or has any knowledge about the crime to call Detective Angel Sanchez at (650) 853-3144, the East Palo Alto Police Dispatch at (650) 321-1112, the East Palo Alto Tip Line at (650) 853-8477 or the East Palo Alto murder hot line at (888) MURDER-0.