SUGAR LAND, Texas -

A string of home burglaries in Sugar Land leads police to believe thieves are getting better at out-smarting home alarm systems.

Police said the crooks are breaking into the homes through a back window or door so passersby won't see them. But once inside, burglars were also very careful to make sure nothing triggered the home's security system.

One homeowner returned from a 10-day family vacation to find her home in the Glen Laurel subdivision ransacked and her 82-year-old mother's antique jewelry stolen.

"My mother couldn't sleep. Right now, she's still scared," said the victim who did not want to be identified.

One street over, another family came home from vacation Tuesday morning to find the same damage. And police said it was the same scenario.

"The suspects remained in the master bedroom or adjoining rooms, and stayed away from the living room or the den, where typically, there are motion sensors that would activate a security alarm," said Doug Adolph with the city of Sugar Land.

Police were called to a third burglary Monday night in the Ashford Lakes subdivision. They said someone tried to break in through a back bathroom window. But when the alarm went off, the burglar ran off.

Despite these cases, the city of Sugar Land said burglars are not breaking into homes more often.

From Jan. 1 to June 5, 2011, there were 83 home burglaries in the city of Sugar Land. There have been 80 for the same period this year.

Sugar Land police remind homeowners to sign up for the city's house watch program if you will be away for an extended period of time. Police will stop by and check your home free of charge. They will also send an officer to your home to perform a free security assessment.