Police are increasing their patrols to coincide with the increase in the number of people visiting area shopping centers this time of year.
There have been several armed robbery attempts recently in Anne Arundel and Baltimore counties.
The most recent case happened Sunday afternoon at the Walmart store in Glen Burnie, off Ordinance Road near Route 2.
A woman was leaving the store with items she bought, when two boys ages 11 and 14 approached her.
"The suspect walked up to a lady in the parking lot and pulled out a knife and try to rob her," said T.J. Smith, a spokesman for the Anne Arundel County Police Department.
The woman got away and later identified the suspects. Police arrested them at another store nearby and gave them juvenile citations.
"That's troubling on many different levels, that we have and 11 and a 14-year-old out committing this type of crime, and an 11 and 14-year-old that are unattended and behaving this way," Lt. Smith said.
Last Friday police in Baltimore County say two men robbed a shopper inside of Towson Town Center. The suspects had a knife.
Police have increased patrols at the mall; they say anyone who appears to be careless or unaware can look like an easy target.
There was also another robbery in Anne Arundel County last week. The victim used Facebook to arrange a meeting to sell a pair of tennis shoes on Wednesday, along Nursery Road in Linthicum.
When he got there, two young men walked up, punched him in the face, and took the shoes.
One of the suspects has been identified as 18-year-old Zachary Lynch; a 16-year-old has also been arrested.
If you plan to buy from someone you don't know, police say arrive at the location at least an hour early to check out your surroundings.
"And make sure it is a public place," Smith said. "Meet them in a location that has lights, meet them in a location that has surveillance cameras something like that."
No one was injured in any of those incidents; and police don't believe any of them are related.