Investigators say the robber rode a dark-colored motorcycle and had the cash stashed in a black backpack. Money was flying out of the backpack along the highway as the robber made his getaway.

The FBI says some people stopped to pick up cash along the highway. Agents say they should contact the FBI and return the money immediately. None had been returned as of Friday afternoon.

The robber hit a Wells Fargo branch Thursday morning. He showed a teller a weapon, then reached over the counter and took an undisclosed amount of money.