A mother was arrested on suspicion of child endangerment after a deceased infant was found in an apartment in Perris Thursday morning, according to the Riverside County Sheriff’s Department.

A resident flagged down a motor enforcement officer from the Perris Police Department in front of an apartment building in the 900 block of D Street about 8:12 a.m. to advise of a “foul odor” coming from a neighboring unit, a sheriff’s news release stated.

The person requested that the officer do a welfare check on the occupants.

After gaining access to the apartment, the officer found the dead baby inside, along with a woman in her 20s and a 2-year-old child, the release stated.

The gruesome discovery prompted sheriff’s homicide investigators to respond.

Susan Chavez, 28, was arrested on suspicion of child endangerment, according to the release. She was transported to the Robert Presley Detention Center in Riverside.

Chavez was the mother of both children, according to sheriff’s Deputy Mike Vasquez.

The toddler received medical attention and is in protective custody.

An autopsy will be conducted on the infant to determine a cause of death.

Anyone with information about the baby’s death has been asked to contact Investigator Posson of the Central Homicide Unit by calling 951-955-2777.

KTLA’s Feven Kiflegiorgis contributed to this story.