Alex Doncevic is a character in the novel Dexter by Design. Initially believed to be a suspected murderer he turns out to be Dexter's first more or less innocent victim in the Novel continuity.
Plot
Dexter by Design
After four bodies appeared in one day, staged in some form of modern art, Dexter is puzzled why is his Dark Passenger doesn't have any idea about it. As the bodies are some twisted interpretation of tourist attraction, Dexter and Deborah visited The Greater Miami Convention and Visitor's Bureau and find out that they were supposed to be harmed by attacks in the first place as they have a DVD sent to them which depcits what is supposed to be murders as well as people reacting to them in the fashion of tourist commercials.
After picking up a list of recently fired people as their suspects, they visit a few of them and then they have an argument about Dexter being a serial killer. Because of that, when they visit yet another suspect, a Canadian citizen who used to work as a writer for bureau before getting fired and even removed by security from the place, Dexter remains in the car. Meanwhile, after showing her badge, Deborah gets stabbed. Dexter catches a man who is supposed to be an attempted murderer, Alex Doncevic, but his lawyer, Simeon has him freed.
Nearly improvising, Dexter kills Doncevic the same night using the instruments he supposedly used to kill his victims, especially surgical saw. Dexter is greatl puzzled by Doncevic's last word: "Smile".
It later turns out that Doncevic wasn't the killer and wasn't even an attempted murderer - the four bodies were stolen from the morgue and the knife which was used to stab Deborah had other thumbprints on it, those of Weiss.
Later Dexter recieves an e-mail with a YouTube video of him killing Doncevic. Doncevic's murder has his lover, Brandon Weiss to go murderous.
TV Series
It should be noted that characters of Oscar Prado and Jonathan Farrow from the TV Series are very similar to Doncevic - first one being an attmepted murderer killed by Dexter (and his first more or less innocent victim, as well as partially improvised like Doncevic) and second one being even more innocent victim an alleged murderer who turned out to be innoncent, though his personality and art were very disturbing and psychotic. Both also had their lawyers to get them free of charges and both were framed by their associates. It should be noted, though, that despite Farrow seems to be at least partially based on Doncevic the gap between novel and filming of Season 4 is to small to say for sure.
He's also similar to Viktor Baskov as his murder by Dexter leads into a serious killing spree by his lover who snapped.
Victims
While Doncevic has no confirmed killed he was alleged and suspected of killing four people who turned out to be corpses stolen from morgue. As Masouka says, though “It's still a felony [...] Stealing a corpse, desecrating the dead, something like that. Endangering public health? I mean, it's gotta be illegal.”
He also may be considered an accomplice to an attempted murder of Deborah Morgan as he didn't gave up Weiss.