A security guard was ambushed and killed Friday outside a bank in northwestern Indiana before two armed men entered and demanded money, authorities said.
The shooting occurred at First Midwest Bank in Gary.
One suspect was subsequently arrested, the Lake County sheriff's department said.
The FBI is taking over the investigation, Sheriff Oscar Martinez Jr. said.
The department “will assist in whatever way we can in bringing these suspects to justice," Martinez said. “I would like to offer my deepest heartfelt condolences to the family and friends of the security officer who was killed.”