A Lansdowne man is being held on $500,000 bond after police charged him with four robberies in the Columbia Town Center area.

Howard County police said Andrew Deangelo Blackstone, 23, was charged with armed robbery, robbery, assault and other offenses.

Blackstone is charged in four incidents between June 6 and July 18, police said. In all four, he targeted womens’ purses, at times pushing or grabbing them and — in at least one incident — showing a knife.

Police said they increased patrols in the area of 10400 Swift Stream Place after receiving the reports. They said they eventually identified Blackstone as a suspect, adding that he often stays with a friend in the area.