Process of Elimination

"Question: Why does the Holiday Killer always use the same model of gun?" Riddler spun his cane as he asked, and seeing that no one paid him any attention, he answered himself.

"Answer: He bought them in bulk, or... this kind of .22 pistol is very light, easy to grip, and couldn't be more suitable for a lady... a cat-lady."

"Catwoman?" Carmine remained noncommittal. "Go on."

"Before this, she broke into Mr. Carmine's mansion and hurt Mr. Carmine."

"And because of that, she got a sky-high bounty on her head."

"When plagued by the bounty, she discovered the best defense—was a fierce offense."

"...Is that so?"

"Question: Why did the killer shoot Alberto Falcone?"

"Answer: Because he could."

Carmine did not speak, his face darkening.

"Uh... I mean... Alberto wasn't involved in the Falcone business... so could this kind of assassination be a personal act of revenge?"

Riddler continued, "An hour before Alberto died, Johnny Vitti was shot to death at the Police Department, and his mother, Kara Viti, happened to be on the same yacht as Alberto."

"Besides, who could get close to Alberto without arousing his suspicion?"

"In that regard, it's almost like an eye for an eye, a son—for a son." Riddler said with a sigh.

"I heard Batman smashed your jaw?" Carmine suddenly asked.

"Uh... yes." Riddler nodded.

"If you don't want your jaw smashed again, don't use that tone of voice with me!" Carmine said coldly.

"There's another suspect, Julian, nicknamed Calendar Man. His actions are always tied to dates; he's a very paranoid guy. He always commits crimes on special dates or holidays, and he even changes his outfits according to the meaning of the date." Riddler honested up a bit and sold out his fellow inmate.

"According to Arkham Asylum's records, he has