Authorities say that the suspect has been entering either late at night or early in the morning. And Ontario police say that this has happened so far 27 times.
"We're concerned because it has been escalating. During these last summer months it has gotten to the point where this guy is getting really bold. He is not really shy about what he is after. That is why we are concerned, especially if a female is home by herself or with her children -- that is an obvious concern that we want to address," said Officer Anthony Ortiz, Ontario Police Department.
Police officers and explorers spent Tuesday canvassing all 293 units in the complex. Guadalupe Lutz was shocked to hear what's been happening all around her.
"I'll just be more aware to see if anything strange happens and look to see if anyone is there that doesn't belong, maybe I'll take a second look," said Lutz.
Police say 90-percent of the population here speaks Spanish. So translators were on hand.
One woman said she might have scared a potential intruder off a couple of months ago.
Police say so far the intruder has not shown any signs of violence. But until detectives find the suspect residents are still very concerned.
"It makes me kind of scared because I have a daughter and wife at home. And for something to happen like that in this area is just terrifying," said resident Matt Hayward.
If you have any information about these burglaries, please call the Ontario Police Department at (909) 395--2833.