The incidents happened in or near the Canby Park Shopping Center since November 28th.
The most recent incident happened at 5:55 p.m. on Tuesday.
According to police, a 64-year-old man was robbed by a group of five teenage boys as he walked along the rear of the shopping center.
Police say he was surrounded by the group and one of the teens was armed with a handgun.
They demanded money from the victim, who opened his wallet to show them it was empty.
The teens then ran away on foot.
The suspects are all described as black males, approximately 14 to 16 years old, standing about 5'6" to 5'9" tall. All were wearing hooded sweatshirts, police said.
This is the same area where there were five armed robberies of pedestrians between August 31st and Sept 17th.
Police say many of the armed robberies, including the one on Tuesday night, happened in the stairs that lead from the shopping center down to surrouding residential streets.
The first armed robbery occurred around 8:40 p.m. on August 31st. A 35-year-old woman was robbed while walking down the stairs that lead down to Robinson Road.
On September 6th, a 30-year-old man was approached by two teens around 9:30 at night.
There were two incidents on September 8th, one at 8:00 p.m. and one at 8:10 p.m.
The final September robbery in occurred on the 17th, when two suspects tried to steal a woman's laptop.
On November 28th, a 19-year-old man was robbed around 6:00 p.m. by four suspects - including one with a gun - at the nearby intersection of Maryland Avenue and Germay Drive.
On December 3rd, a 33-year-old man was approached by four suspects by the steps.
The crimes have neighbors, and people who work in the shopping center, looking over their shoulders.
"Around 6:00 we just make sure the door is closed, the alarm is on and we have a ride," said Angelica Torres of Canby Park.
State police are warning people to avoid the rear of the shopping center after dark. They're also asking anyone who may have information about the teen suspects to call Delaware Crime Stoppers at 800-TIPS-3333.