Four arrests have been made in connection with a series of robberies targeting seniors in Chicago and northwest Indiana.Clever gang members have taken advantage of police restrictions in other jurisdictions for years, say Chicago police. But a collaboration of city and suburban cops in Illinois and Indiana appears to have caught some suspects by surprise with more than 500 arrests, including four men for series of robberies targeting seniors. For months, routine trips to run errands have been taken with great care in the South Side community of Hegewisch. At Chantilly's Beauty Shop, some of their clients have been the victims of assaults and robberies. "This is very frightening for this neighborhood. So it's not just Hegewisch but the East Side and all over," said Amelia Gillespie, Chantilly's Beauty Shop. "People are carrying mace. They are being followed home from various stores and banks. And everybody's kind of on the watch now," said Joe Gillespie, resident. On Friday police officers with the Illiana Task Force announced a multi-jurisdictional investigation of robberies leading to four arrests. "We noticed that our gangbangers and other criminals utilized our borders to commit crimes. They would commit crimes in Chicago and flee to the neighboring suburbs and into Indiana," said Cmdr. Dana Alexander, Chicago Police Department. Police say the suspects watched elderly patrons of grocery stores leave then followed them home. In January there were two robberies and assaults in Burnham of elderly residents and more cases were being investigated. In one block of Hegewisch, a victim - who did not want to be identified - said she and her 88-year-old husband were beaten and robbed in December. She says the suspects approached them as they got out of their car after running errands and forced them into the house at gunpoint. Over the weekend, a mother and daughter were targeted in another block of Hegewisch. As the suspects fled, police say they recognized the car from surveillance at the Indiana-Illinois border. With the help of several police departments, four Gary men were arrested, and police say they have been linked to 24 robberies. "I have a mother in the neighborhood. So I know I feel this personally that everyone is living in a state of fear. And this is a great announcement. It's great police work. And it's really let the community feel that they're that much safer," said Ald. John Pope, 10th Ward. The Illiana Task Force started in 2006. Police began sharing information. But when they saw a pattern of attacks on the elderly they began working the case together.