The crash happened just after 9:30 p.m. on Garey Avenue and County Road near the 60 Freeway. Police said a suspect they were chasing - who was identified as 31-year-old Marshall Judson - struck a Ford Fusion, killing the two occupants inside.
Family members who spoke with ABC7 on Thursday said the woman who was killed was 8 and a half months pregnant.
According to investigators, the incident began earlier Wednesday night when officers responded to a domestic violence call on E. Tenth Street. While officers were speaking with the victim, police said Judson returned to the scene driving recklessly and intentionally rammed a parked patrol car.
That act escalated the investigation into a felony pursuit.
"Elevated into an assault with a deadly weapon on the police officers and their vehicle by the suspect using his vehicle. So, in that case, you have two egregious felonies which warrant a valid pursuit," said Bruce Thomas, a law enforcement expert.
Police said Judson fled, leading officers on a short chase through Pomona that ended in the deadly crash. Video from the scene showed debris scattered across the street, including a baby car seat.
Judson was taken into custody. Police said they found a "firearm and miscellaneous firearm components" in his car. Judson also did not have a valid driver's license, they added.
He's facing charges of vehicular manslaughter, assault with a deadly weapon on a peace officer, driving under the influence, driving without a valid license, felony evasion, and firearm-related charges.
The incident remains under investigation.