They say one of the suspects confronted the homeowner in his driveway and forced him into his house at gunpoint.
Investigators say once they were inside, the man, his wife and 9-year-old son were bound.
The man was reportedly choked until he gave the suspects cash.
The victims waited hours before calling police because the suspects threatened to return and harm or kill them.
Investigators would not say whether the home invasion robbery is related to another robbery last Wednesday about 10 minutes away in the 300 block of West Duarte Road.
In that case, two teenagers confronted an elderly man taking groceries out of his car, punched him in the face and took his wallet containing $1,200.
Investigators say when his wife came outside, they pushed her to the ground and took her wedding ring.
The suspects taped the woman's mouth and tried to zip tie their wrists before leaving.