RELATED SLIDESHOW: Pictures of the bank robbery suspect
The latest crimes happened at the Bank of America branch at 4610 City Avenue at 12:12 PM and then immediately after that the PNC Bank branch located at 4060 City Avenue.
Mitchell has been charged with the robbery of the FirstTrust Bank branch located at 1515 Market Street on September 29, 2009, and the attempted robbery of the Polonia Bank branch at 2133 Spring Garden on September 28, 2009.
The FBI said Mitchell is also considered a suspect in the robberies of the FirstTrust Bank branch at 1901 Walnut Street on September 25, 2009, and the TD Bank branch at 4020 City Avenue on October 4, 2009.
Mitchell is described as 5'9" tall, 210 pounds, with a stocky build, a goatee-type beard and mustache, and prescription eyeglasses.
There may be a reward available for Mitchell's capture. Anyone with information is asked to call the FBI at 215-418-4000 or the Philadelphia Police Department.
The FBI said the two bank robberies on Wednesday brought the total number of bank robberies in the city of Philadelphia up to 96 so far this year compared to 70 for the same period last year. Of those robberies this year, 16 are classified as "armed" compared to 6 armed robberies for the same period last year.
You can get the latest crime statistics from the Philadelphia Police by CLICKING HERE for the force's crime data mapping site.