Surveillance video still of the Geezer Bandit.

Surveillance video still of the Geezer Bandit. (FBI)

SAN LUIS OBISPO, Calif. (KTLA) -- The so-called "Geezer Bandit," who's wanted in a series of robberies in Southern California, may not be old at all, the FBI says.

Agents say they have looked at surveillance video and interviewed dozens of witnesses.

They think the bandit may be a younger man wearing an elaborate mask and gloves.

Investigators also say that, when a dye pack in a bag with the money from a Dec. 2 robbery in San Luis Obispo exploded, the suspect sprinted away -- hardly the gait of an elderly man.

The FBI thinks he may have fled the scene of that robbery in a white BMW.

Authorities say he also dropped a day planner, which is now being reviewed at the FBI crime lab in Quantico, Va.

The Geezer Bandit's robbery spree began in August 2009.

Of the 16 robberies linked to the suspect, 11 occurred in San Diego County.

A $20,000 reward is being offered for information leading to an arrest.

The bandit has been described as 60 to 70 years old.

He demands money and threatens the tellers with a gun.

Anyone with information is asked to call the FBI at (858) 565-1255.