The FBI has questioned a Southern California company that makes masks as part of the investigation into the "Geezer Bandit" robbery series, 10News learned.The FBI has been exploring the possibility the man known as the Geezer Bandit wears a mask after some witnesses from the first 11 bank heists said the robber looked to be wearing one.In the latest robbery in Bakersfield, multiple witnesses said the man had donned a mask.Sources told 10News the FBI has contacted Van Nuys-based SPFXMasks, a maker of realistic masks. While the FBI won't confirm the name of the company, sources told 10News it's a theory that is being working on."We have been in contact with people with knowledge of these types of masks," said Darrell Foxworth, spokesman for the FBI in San Diego.The FBI won't say if they're leaning toward the mask theory, but one reason why they are looking into the possibility may have to do with a previous case in the Midwest.In Ohio, a white man recently pleaded guilty to robbing banks wearing the mask of a black male made by SPFXMasks. It was so realistic police initially arrested a black man in connection with the crimes.Now, investigators might be wondering if the Geezer Bandit is in fact wearing the SPFXMask creation named "The Elder."10News asked Rusty Slusser, owner of SPFXMasks, to compare his mask to the Geezer Bandit."With surveillance pictures alone, I just can't tell," said Slusser.While he declined to comment on the FBI investigation, Slusser admitted his masks are expensive -- some can be thousands of dollars -- because they're so realistic.