Shots rang out at a Blue Island bank during an attempted heist witnessed by a customer Wednesday morning in the south suburb. About 9:45 a.m., a person tried robbing an armored truck parked outside the U.S. Bank at 11960 S. Western Ave., a city official of Blue Island said.A witness told the Chicago Sun-Times that he was inside the bank when he heard a security guard shout at them to drop to the ground.“I dropped to the floor and heard the security guard tell someone to lock the door, but I didn’t see what was happening,” he said.Shortly after dropping to the ground, the witness said he heard gunshots and glass shatter.Police taped off access to the bank and placed evidence markers next to spent shell casings. The glass door to the bank was shattered. A gun was seen on a sidewalk outside the bank.The FBI is investigating, according to a spokesperson for the agency, who did not share anything else.It's unclear if anyone was shot or injured. The Blue Island Fire Department couldn't be reached for more information. “I’m OK,” the witness said. “I just want to know what happened.”Contributing: Anthony Vazquez A gun lies on the ground as Blue Island Police investigate the scene of a shooting at the U.S. Bank branch on Western Avenue on Wednesday.Anthony Vazquez/Sun-Times A shattered door is seen at the entrance of the U.S. Bank branch on Western Avenue in Blue Island, the scene of a shooting Wednesday morning.Anthony Vazquez/Sun-Times ...read more read less