Jamieson, Fausset and Brown on 2 Kings 14:19-20

19-20. they made a conspiracy against him in Jerusalem--Amaziah's apostasy (2Ch 25:27) was followed by a general maladministration, especially the disastrous issue of the war with Israel. The ruinous condition of Jerusalem, the plunder of the temple, and the loss of their children who were taken as hostages [2Ki 14:13, 14], lost him the respect and attachment not of the grandees only, but of his subjects generally, who were in rebellion. The king fled in terror to Lachish, a frontier town of the Philistines, where, however, he was traced and murdered. His friends had his corpse brought without any pomp or ceremony, in a chariot to Jerusalem, where he was interred among his royal ancestors.

2Ki 14:21, 22. Azariah Succeeds Him.