Murders by Niko Bellic

There are many hit missions in Grand Theft Auto IV, and Niko Bellic has accrued the greatest body count of any GTA protagonist thus far, with over 80 possible named murders. This is most likely because he works as a hired gun instead of a creating a criminal empire and because GTA IV has named most chracters instead of going after unnamed thugs.

The following is a list of his intended targets ("collateral" murders such as those of unidentified gunmen, pedestrians, or police are not included), including random characters, Most Wanted, optional killings and possible killings he may attempt.

Murders

Main story

Bellic committed several murders during the Yugoslav Wars, but they do not count as murders during gameplay.
Kalem Vulaj, Bledar Morina and Dardan Petrela – They are the first murders by Niko in Liberty City. Niko beat them to death in the defense of Roman Bellic. And when Dardan attacked Roman.
Vladimir Glebov - Niko shoots him in the eye for sleeping with Mallorie Bardas.
Lenny Petrovic - Murdered on orders of Mikhail Faustin.
Jason Michaels - Murdered on Faustin's order for "messing around" with Anna Faustin.
Lyle Rivas - Chased and killed on orders of Bruce Kibbutz.
Mikhail Faustin - Murdered on orders of Dimitri Rascalov, and to appease Kenny Petrovic.
Tom Rivas - Murdered for not paying off his debt to Brucie Kibbutz.
Tom Goldberg - Murdered for giving Francis McReary potential legal trouble.
Blackmailer - murdered for blackmailing Francis McReary.
Clarence Little's Associate - murdered on orders of Francis McReary.
Marlon Bridges - Murdered on Playboy X's orders.
Charlie - Murdered for having attempted to arrest Niko Bellic, Trey Stewart and Johnny Klebitz.
Jayvon Simson - Murdered for ratting on Dwayne Forge.

Trunchez Brothers - Murdered so that Dwayne Forge can get the Triangle Club back.
Oleg Minkov - Murdered on orders of The United Liberty Paper.
Adam Dimayev - Murdered on orders of The United Liberty Paper.
Teddy Benavidez - Murdered for failing to pay Ray Boccino.
Roman's Kidnapper - Murdered for -as his name suggests - kidnapping Roman.
Kim Young-Guk - Murdered on orders of Jon Gravelli for lowering the value of US currency.
Aiden O'Malley - Murdered for trying to testify against Derrick McReary.
Bucky Sligo - Murdered on Derrick McReary's orders for threatening the McReary family.
Anthony Spoleto - Murdered on Gerald McReary's orders, to sour the relationship between the Ancelotti Family and the Albanian Mob (who were framed for the killing).
Frank Garone - Same as Anthony Spoleto. Murdered to damage the Ancelotti relationship with the Albanians.
Charles Matteo - Murdered for discovering Phil Bell's role in sabotaging a cocaine deal between the Ancelotti Family and the Russian Mafia.
Isaac Roth - Murdered for threatening Ray Boccino.
Luca Silvestri - Murdered for stealing diamonds from Ray Boccino.
Joseph DiLeo - Murdered in a shootout with Niko Bellic.
John Barbosa - Murdered in a shootout with Niko Bellic.
Jim Fitzgerald - Murdered after causing trouble to Ray Boccino.
Ray Boccino - Murdered for being a potential rat on Jimmy Pegorino's orders.
Anthony Corrado - Murdered for leaking information to the FIB via wire, for James Pegorino.
Dimitri Rascalov - Murdered for betraying and trying to kill Niko (both "Deal" and "Revenge" storyline). Murdered in the cargo hold of the Platypus ship (only in "Revenge" storyline). Also for the responsibility of Roman's Death (only in "Deal" storyline).
James Pegorino - Murdered for killing Kate McReary (only in "Revenge" storyline).

Random encounters

Main article: Random Characters

Eddie Low - Murdered by Niko in self-defense (Eddie Low is a random character, so killing him or even encountering him in the first place is optional).
Clarence Little - Can be spared, although in a later random encounter, he must be killed anyway, unless the encounter is avoided altogether.

Optional

Main article: Choices in GTA IV

Ivan Bytchkov - Niko can let him fall from the building, on Vlad's orders, or help him up.
Cherise Glover - Niko can shoot her in Ruff Rider, or let her live.
Clarence Little - Niko can kill him, on Francis McReary's orders, or let him live.
Adam Dimayev - Appears during Portrait of a Killer. Can be spared or killed.
Unnamed Jewish Mobster - Niko can kill him in the Majestic Hotel or walk away.
Darko Brevic - Niko can either take revenge by shooting him multiple times, or spare him.

Choose between two targets

Playboy X or Dwayne Forge - Both characters ask Niko to kill the other.
Francis McReary or Derrick McReary - Niko can shoot either with his sniper rifle; again, both have asked Niko to kill their opposite number.

Possible murders

Mickey - Can be killed during Uncle Vlad.
Jimmy - Niko can kill him during the mission Clean Getaway. It would change the dialogue with Vlad through the phone.
Vasily - Niko can kill him in a drive-by in the mission Wrong is Right.
Karen - Can be killed during Final Interview.
Alonzo - Niko can kill him, or let him warn Teddy.
Stevie - If the player is quick enough they can kill him after I'll Take Her. He may or may not be the Stevie Niko does the car thefts for.
Frankie Gallo - Can be killed by either Niko, or the LCPD during To Live and Die in Alderney. Either way this will cause dialogue to change with Phil.
John - A surgeon in the Leftwood Medical Center. Can be killed in Flatline.
Doctor Rosem - A doctor in the Leftwood Medical Center. Can be killed in Flatline.
Talbot Daniels - A man who leads Niko to Florian Cravic, Talbot can be killed by Niko before confronting Florian changing dialogue with Roman Bellic and Ray Boccino.

Continuity Error Murders

Luis Fernando Lopez - Can be killed during Three Leaf Clover. Not programmed to be an in-game target. Killing him will not affect the game's storylines in any way, as he will still appear during Diamonds Are a Girl's Best Friend no matter what.
Johnny Klebitz - Can also be murdered during Museum Piece. Same as Luis, not programmed to be killed. Like with Luis, killing Johnny will not affect the story, even though he doesn't appear again. However, he is the protagonist in The Lost and Damned. He was brutally murdered in Grand Theft Auto V during a confrontation with one of the game's three protagonists, Trevor Philips. This was five years after the events of Grand Theft Auto IV and it's episodes.

Most Wanted murders

Main article: Most Wanted Missions in GTA IV