(WBBM) - The FBI has a mystery on its hands, following a bank robbery and shootout in south suburban Homewood this week. Call it The Case of the Missing Money.

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The FBI says the alleged bank robbers were caught red-handed after a shootout with police Tuesday morning on 183rd and Kedzie in Homewood.

The FBI says Justice McCallister, 36, and Tiffany Jones, 23, were arrested after a brief foot chase following the hold-up at a U.S. Bank branch. The getaway driver has not yet been caught.

According to a federal complaint, an audit determined more than $112,000 was taken in the robbery, but that $7,500 of it is unaccounted for.

The FBI is investigating, a spokesman saying it's possible there was a mistake in the audit or that some of the money blew away or something else. The bank is conducting a second audit to be sure of its figures.