John Gill Commentary 2 Kings 21:23

"And the servants of Amon conspired against him, and put the king to death in his own house." — 2 Kings 21:23 (ASV)

And the servants of Amon conspired against him
Some of his domestic servants, and perhaps his courtiers, not on account of his idolatry, but for some ill usage of them:

and slew the king in his own house :
which they had an opportunity to do, being his servants.