Three suspects, believed to be part of a larger group, were caught on surveillance video at one of the homes.
The suspects, described as men in their 20s and 30s, dress to blend in, act like they're lost and ask for directions if someone responds to a knock on the door. If nobody answers, they break into the home through the back.
The group is believed to be responsible for more than three dozen homes in the western San Fernando Valley area since last summer.
Police think the burglars travel in rented luxury vehicles during the day. Once in a home, they first look for jewelry.
In some cases, the "knock knock burglars" have even used pepper spray on dogs at the homes.
In a similar case in Pasadena recently, a woman hid in her closet and called police after burglars broken into her house. Responding police arrested three men and a boy as they tried to get away; they were charged with burglary and also with attempted murder, for allegedly trying to drive into a police officer.
Investigators are looking into a possible connection between the Pasadena break-in suspects and the San Fernando group.