Albert Barnes Commentary 1 Kings 13:28

"And he went and found his body cast in the way, and the ass and the lion standing by the body: the lion had not eaten the body, nor torn the ass." — 1 Kings 13:28 (ASV)

The lion had not eaten the carcass, nor torn the ass - These strange circumstances were certain to draw people’s attention to the matter and cause the whole story to be widely reported. By these means, an incident that Jeroboam would have wished to keep quiet became, no doubt, the common talk of all the people.