How do we break planar connections? (Denizen of Leng)

[keeper0]

My party killed a Denizen of Leng in an encounter. We now find out that they don't really die, just go back to Leng. The denizen then hired a Leng bounty hunter to chase us down across the planes.

How are we supposed to permanently rid ourselves of this pursuer? The rules say that the fast healing and the *BAMF* home upon death are block "on Leng or in areas where planar connections do not function." I have spent a good amount of time trying to figure out an example of "where planar connections do not function" but can't find one. Short of hunting the hunter on Leng, what options do we have?

I could tell a good story about using a binding spell to summon it and kill it, but the body might just wait until the binding expires before returning home. The rules don't seem definitive.

[keeper0]

Update: Nothing like hitting submit on a post to make an answer pop up in your Google search.

Apparently, the RAW solution is Forbiddance.

Are there any other suggestions?

[Meirril]

Suggestion one: Don't kill it. Flesh to Stone is a more or less permanent solution.

Suggestion two: Hit it with Dimensional Anchor and then use some method to trap its soul. Summon Cacodaemon is one method. The easiest to perform actually.

Suggestion three: Send an Invisible Stalker or some suitably powerful Outsider to Leng to visit the Denizen that put the contract on you to deliver a message: Drop the contract or the Denizen will be hunted as well. Don't expect negotiations to go well.