CHICAGO: A mask-wearing gunman opened fire at a shopping mall in Indiana Wednesday, injuring three people, local media reported. An employee at a Target store told Indianapolis broadcaster RTV6 that she heard 15 gunshots. Other witnesses said the shooter was escaping on foot wearing a ski mask and dark clothing. In a briefing to local media, police said the shooter and the worst-off victim, who was in critical condition but expected to survive, knew each other. They reported that after the shooter entered the mall he found the victim and an argument ensued, after which shots were fired. Ricochets likely hit other victims. The suspect was still at large. In the wake of several high-profile mass shooting in recent months, combating gun violence has emerged as a major topic of the US presidential election campaign.