Blood Brothers

Blood Brothers is is the final mission given by Francis McReary in Grand Theft Auto IV. It is unlocked after completing Derrick's final mission, "Tunnel of Death".

Overview
Francis will send Niko a text message telling him to meet Francis in a curb in Algonquin. Francis pulls up in a Landstalker and explains that he wants Derrick dead for "the good of the community", when in reality, Derrick is intending to leak incriminating information about Francis to a reporter, jeopardizing his career in the police force. Francis is meeting Derrick in a park in Lancet to give Niko the opportunity to kill him. Later, Derrick contacts Niko to tell him about the meeting and voices his fear that Francis wants him dead and asks Niko to go to the meeting and kill Francis before he kills him. Niko must now choose between the 2 brothers.

Walkthrough
Drive to the park in Lancet. After Derrick's call, Niko will contact Francis again, who gives you instructions on where to take point. Climb the scaffolding and get to the roof via the window cleaning elevator. Run up to the yellow marker. Niko will get his sniper rifle ready, now is the chance to shoot. Choose between Francis or Derrick, and kill one. If you're going to kill Derrick, make sure to call Francis while on the roof to make him increase the hit payment from $10,000 to $20,000.

Whoever you kill, a cutscene will show either Derrick running away or Francis telling everyone to clear the area, depending on who died.

Francis McReary
If you decided to kill Francis, you get no money, as opposed to the large payment if Derrick is killed.

Derrick McReary
If you killed Derrick, you will get a large sum of money ($10,000 or $20,000 if the player calls Francis while on the rooftop to bump up the hit payment). You also gain the temporary ability to get rid of a 3 star wanted level or less. Either way you still unlock the following mission.

Tips

 * If the plan is to kill Derrick, call Francis right before you are planning to snipe. He will offer a greater reward for Derrick's death. However, if you are planning to kill Francis, it's still a good trick but doesn't give anything.
 * Be careful not to fall off of the building you snipe from. While the building is low, the player character may still be killed if they fall.

Deaths

 * Francis McReary

Or
 * Derrick McReary