Anaheim police, hazmat team investigate after 1 dies, 3 are hospitalized following house party

One person was killed and three other people were hospitalized after they suffered from apparent overdoses at a party in Anaheim on Sunday morning. 
Officers were called to the 1500 block of Benmore Lane at around 1:10 a.m. after receiving calls reporting the emergency, according to the Anaheim Police Department. 
They arrived to find four male adults who were unconscious in front of an apartment complex. All four were rushed to nearby hospitals. 
Police say that one of the men died after arriving at the hospital. He has not yet been identified. 
One is in critical condition while the other two are said to be stable, police reported. 
Investigators say that a white substance was discovered at the scene of the party where the men were prior to the incident. Because of the discovery, a hazardous materials investigation team responded.
The area was contained for about three hours before it was cleared out.
No further information was provided.