Residents are very concerned over the break-ins, with four in just the last two weeks. Police said the thieves take small items, such as iPods, purses and cash, and they're in and out very quickly while residents are still in their homes.
"It's definitely terrifying just knowing somebody was in the house," said Matt Beasley.
He and his family were sleeping when a burglar broke into their home. He said a few items were stolen, but fortunately his children weren't hurt.
"It seemed like they were only there for probably less than five minutes. There were a lot of valuable things that they didn't grab," said Beasley.
This is just one of a string of burglaries in West Covina over the last six weeks. The burglars take advantage of open windows during cool nights and most of the break-ins occurred while residents were at home, which is unusual.
"These are very, usually, experienced thieves. People that really just want to get your items, they couldn't care less if you're at home or not," said West Covina Police Lt. Ron Mitchell.
Police warned residents that leaving windows and doors open is an open invitation to burglars.
Pat Abolton, who has lived West Covina for decades, said she still feels safe and will continue to keep her windows open.
"I've lived here since 1974, never had any trouble. I love it here. I mean, it's always quiet," she said.
However, other residents said they are now keeping a close eye out for any strangers in their neighborhoods and they're not taking any chances.
"I heard about it and I always keep my doors locked - day, night, doesn't matter," said resident Cheryl Gerlach.
Authorities said residents should secure all windows and doors and call the police if they see anything suspicious in their neighborhood.
Detectives said all the break-ins are similar, but they aren't sure if they're being done by the same person. Anyone with information about the burglaries should call the West Covina Police Department at (626) 939-8500.