He was an internet blogger who killed his online rival.
Benjamin Alvaro was a man engaged in an online war with a fellow blogger named Denny Foster. One day, this war escalated when Ben paid a visit to Denny's comic book store, grabbed a snow globe and bashed him over the head, resulting in his death. After he realized what he did, he went into hiding to avoid the police. He was eventually caught by Lieutenant Maria LaGuerta and Sergeant James Doakes.
Alvaro is portrayed by the comic book artist, Tone Rodriguez, who also contributed to the art of The Dark Defender, a fictional non-published comic book in Dexter's universe. Ironically enough, in the series Denny Foster was the creator and artist of the comic and Alvaro portrayed his killer, who prevented it from being published.