Snape killed Dumbledore because:
1. Dumbledore was already dying.
2. Dumbledore asked Snape to kill him.
3. If Snape didn't kill Dumbledore, Draco would have had to and Dumbledore didn't want Draco's soul ripped apart on his behalf.
4. Snape made an Unbreakable Vow with Narcissa Malfoy that he would kill Dumbledore if Draco failed to do so.
5. It would land Snape firmly in Voldemort's good books so that Hogwarts would be under the control of Snape and not the Carrows.
6. If J.K. Rowling hadn't killed Dumbledore somehow, the final battle would be postponed for too long.
no. in the 6th snape kills dumbledore. in the 7th, voldemort kills snape and harry kills voldemort
no he does not severus snape kills dumbledore
Snape kills Dumbledore
He is no way good, but he does work for Dumbledore, even when he kills him, he does it on Dumbledore's order.
First, Professor Mcgonagall. Then Snape.
It is unknown if Kreacher dies, but he does fight in the Final Battle.
No. The only other time Dumbledore is in the Books is in the 7th book. But he is not alive.
Yes and No. Right before the fall of the Potters and Voldemort, Snape switched to being in the service of Dumbledore. After Voldemort fell, Snape was used by Dumbledore to keep a lookout in case of Voldemort's return, as well as to keep an eye on the remaining Death Eaters not in jail. Once Voldemort returned, Dumbledore had Snape serve Voldemort, yet he was to rely the info back to Dumbledore. Snape being a servant of Dumbledore is very easy to miss in the books and the movies. In the Half Blood Prince, when Snape kills Dumbledore, it was due to the fact the Dumbledore had arranged for Snape to kill him, if Harry was to kill Voldemort.
Severus Snape kills Albus Dumbledore,Tom Riddle kills Severus Snape(and finally Tom Riddle kills himself accidentally, but he has never been headmaster, so that doesn't matter)
yes, snape kills professor dumbledor with the killing curse in the half-blood prince
When snape turns on Dumbledore (at least you think he does) at the very end of the book and kills him. He actually kills him but it is all part of a plan Dumbledore had in the 7th book
Because Severus Snape is refereeing the game, and he thought that in the match before, Snape had been cursing his broom, so with Dumbledore watching, he thinks that Snape won't do anything while Dumbledore is watching.