WASHINGTON — A string of burglaries in Montgomery County, Maryland has a common theme: two people pose as utility workers or salespeople to get inside the homes.

Three homes have been burglarized this way over the past month, according to police. Each time, the targets appear to have been the elderly.

The woman, described as being white and in her 20s, walks up to the door and says she’s with the power company and needs to check the meter.

She also has pretended to be selling and installing pipes to get into a home.

A man, described as white or Hispanic in his 20s, plays the role of supervisor.

But instead of doing any maintenance, the two have made off with credit cards and other goods.

Montgomery County Police believe the same man and woman are behind each crime.

The victims have all been 78 and older. Their homes are in Silver Spring, the Kensington area and Rockville.

Police suggest asking for a worker’s profession identification if someone comes to the door asking to check a meter.