An investigation was underway Tuesday after the bodies of three people in various states of decomposition were found in a Long Beach apartment the previous night, authorities said.
Officers were sent to an apartment complex around 6:50 p.m. Monday after someone called about a "foul odor" coming from one of the units, according to Long Beach Police Department spokeswoman Nancy Pratt.
When they arrived, they found the bodies of two males and a female inside, Pratt said.
The victims were identified only as a Hispanic man in his 50s and a Caucasian woman in her 30s, according to Lt. Fred Corral with the Los Angeles County Department of Coroner. The third person was listed as "John Doe."
Some of the bodies were already decomposed by the time they had been found, according to Corral.
It was not immediately known how long the victims had been dead when the discovery was made. Their relationship to one another was still being determined.
Investigators were looking into the cause of death, but Pratt said a large portable propane heater capable of producing deadly levels of carbon monoxide was found inside.
The type of heater discovered is meant for outdoor use, she added.
No further information about the case was available.
KTLA's Justin Burton contributed to this report.