A Southern California probation officer shot and wounded her husband and opened fire on responding police, who subsequently found the woman and two children dead inside her home, authorities said.

Police in Ontario, California reported an officer-involved shooting about 2:30 a.m. Saturday, NBC Los Angeles reported. Responding officers found a man outside the home with life-threatening gunshot wounds, the station reported.

The situation evolved into a standoff with shots exchanged, according to NBC Los Angeles. Hours after its initial report on the gunfire, the department said on Twitter, "Ontario Police have made entry into the home and discovered the suspected female and two juveniles are deceased inside the residence."

Police told NBC Los Angeles the shooter was a San Bernardino County Probation Department officer. Department Chief Michelle Scray Brown said by email, "We won’t comment until her name is released."

A neighbor told NBC Los Angeles he heard loud yelling and five gunshots before authorities arrived.

"Our house was evacuated to allow them access to the perimeter," Jason Castellanos said. "They seem just like a normal, average family."

The condition of the man shot was not immediately known. So far there were no reports of responding officers being injured.

NBC News reached out to Ontario police but did not receive an immediate response.