Who Killed Saul?

There are two plausible scenarios:

1. It happened as the Amalekite said.

2. The Amalekite embellished the story thinking he would be rewarded for helping David become king.

In scenario 1, though Saul's armourbearer presumed Saul was dead, Saul was 'still kickin' and revived when the Amalekite came by.

In scenario 2 the Amalekite came upon the scene and discerned what had happened, then claimed credit.

In either situation, David had resisted making himself king for many years as Saul had tried to kill him, and having had many opportunities. If the man had known David at all, he would have distanced himself from the killing itself, and merely brought the crown back to David and wept bitterly before him.