Albert Barnes Commentary 2 Chronicles 25:27

"Now from the time that Amaziah did turn away from following Jehovah they made a conspiracy against him in Jerusalem; and he fled to Lachish: but they sent after him to Lachish, and slew him there." — 2 Chronicles 25:27 (ASV)

After the time ... - The writer means that Amaziah's violent death followed his apostasy. This did not happen immediately—it was at least 15 years after the events of 2 Chronicles 25:25—nor was it, from a human perspective, a direct result of his actions. Rather, his death came as a divine judgment, completely fulfilling the prophecy in 2 Chronicles 25:16.