Frankie was a crook working for Rupert Thorne.
History
Frankie led a group of thugs that stole armaments from the US Army. They were holed up in an old warehouse, surrounded by police. Batman snuck in and disposed of them. Frankie and his men were arrested. Upon his arrest, he kicked dirt at D.A. Harvey Dent, who went mad and assaulted him in front of the press. It took several police officers and Commissioner Gordon to save Frankie.
Due to a mistake in the warrant, Frankie and his crew got out of jail, and returned to active service. Frankie was part of the team that picked up Dent and brought him to an abandoned factory. There, Thorne hoped to coerce Dent into cooperation. Batman showed up, and Frankie managed to pin him down. As Thorne fled and Harvey chased him, Frankie fired a machine gun at the latter. Knocked out of balance by Batman, stray bullets hit an electricity case, setting off an explosion that brutally maimed Dent. After escaping from the hospital, Dent—now Two-Face—robbed Thorne on several occasions.
Frankie and Candice impersonated police officers in order to get Dent's fiancée, Grace Lamont, to cooperate. In private, Frankie was not confident that Dent would come out of hiding, but Candice reassured him Harvey's feelings for Grace were too strong for him to stay away. It paid off, and Thorne raided the Wild Deuce club where the two were meeting. Thorne ordered Frankie to kill them both, but Batman roped him in before he could fire. Frankie got loose and attacked Batman, but was finally knocked out when the Dark Knight hit him in the head with a plate. He was arrested soon after.
Frankie eventually got out and returned to work for Thorne. He caught Robin snooping on the roof, trying to break in. Robin was trying to figure out who abducted Harvey Dent from the hospital. After denying any involvement, Thorne ordered Frankie to throw the Boy Wonder off Gotham Gate Bridge. Though Frankie did succeed in throwing Robin off the bridge, he never hit the water. He broke out of his ties and fired his batrope. He then swung through the car, knocking Frankie and his accomplice out of the car.