Police say three suspects, wearing dark clothing and bandanas over their faces, knocked on the door of the apartment, asked for an unknown person, and then pushed their way in. At least one of the men was armed, according to detectives.
"That's got to be shocking. You just open the door, and the next thing you know, you're being a victim of a crime," said the victims' neighbor Victor Morales.
Two adults and two children were tied up but were not hurt.
Investigators say the suspects left with a 52-inch flat screen TV, a PlayStation unit, video games and a computer.
It's unknown if those items were Christmas gifts, but authorities say that home invasion robberies do spike during this time of year, and people need to be careful.
"The most important thing to remember about home invasion robberies is common sense. Lock your doors, lock your windows," said Steve Whitmore of L.A. County Sheriff's Department.
"When somebody knocks on your door or rings the doorbell, make sure you look through and see who it is, whether you have a peep hole or you have a front door glass. Make sure you know who the individual is. If you do not know who it is, do not open the door," advised Whitmore.
In this case, the suspects were able to walk right up to the residents' home even though there is a security gate outside the apartment complex.
"The gate system over here, sometimes people will park on the side, and wait for an actual resident to go in, and they'll follow them in," described another neighbor Jim Wilkins.
This is why authorities say people should always be vigilant before and even after the holidays.
"The problem is, once they start throwing all the empty boxes in the trash bins, people know what people purchased," said Morales.
Authorities are looking into another home invasion robbery that occurred last week in Monterey Park. In that incident, the victims were also tied up, and the suspects took off with a Porsche.
If you have any information on this crime, you are asked to call the Downey Police Department at (562) 904-2340.