A bank robber who hit the Central Bank at 2120 Hennepin Av. in downtown Minneapolis on Tuesday morning carried a bag that authorities want to know more about.

Saying they want the ­public’s help, the FBI said the insignia or emblem on the bag he used is of particular interest to investigators.

The robber, described as a black male with a dark complexion, about 6 feet, 180 pounds, and 30 to 40 years old, was wearing a dark-hooded sweatshirt, dark pants and dark New Balance tennis shoes and carried a white bag, which can be seen on the bank counter in a surveillance photo.

He walked into the bank at 10:45 a.m. brandishing a black pistol. He demanded cash from a teller and ran off with U.S. currency. The FBI notice didn’t say how much he took.

The FBI is offering a reward for information that helps them identify and arrest the robber, the agency’s Gregory Boosalis said.

About 5,000 bank robberies occurred nationally in 2011, the most recent year for which statistics are available. The robbers used a handgun in about a quarter of the cases.

Matt McKinney