It appears the violence involved an altercation among the three people and investigators are not looking for any other suspects.
The victims were found dead in a storage unit on the 1200 block of East Chestnut Avenue around 4:25 p.m., according to police. A third victim, a man described as being in critical condition, was transported to a nearby hospital.
Detectives say it's unknown yet whether they were stabbed or possibly shot.
"Our detectives believe that some type of altercation happened with the three individuals - possibly a stabbing, possibly a shooting," said Natalie Garcia, public information officer for the Santa Ana Police Department.
Police say the incident does not appear to be gang-related.