Police are investigating whether the armed robbery of a Brinks truck on Tuesday outside a Philadelphia-area store is related to four other attacks on armored vehicles in and around the city this summer.

Three men were charged with stealing over $2 million from a Brink's truck in Philadelphia, the first in a string of heists in the area this summer.

One of the suspects is a former Brinks employee who had recently been fired. The robbery was one of five similar crimes in the area in less than two months.