It's difficult to say whether Alaric was actually himself when he became a new Original vampire, as he wasn't technically possessed by any other beings. However, he was definitely evil, and a ruthless killer to boot. Original Alaric hated all vampires and sought to kill them all.

Does Alaric become evil?

Esther Mikaelson's Intervention

Every time Alaric died, Esther Mikaelson — you know, the Original Witch — manipulated his spirit before he resurrected, leading to Alaric's dark alter ego. This "Evil Alaric" came out while regular Alaric experienced black-outs and essentially became a blood-thirsty vampire hunter.

Is Alaric innocent?

Meredith accuses Alaric of the town's murders, but drops all charges, and gives evidence supporting his innocence. Later that night, she comes over to Elena's house and explains that Alaric really is the killer and he's going crazy.