Tirar la piedra y esconder la mano

[ROBINDESBOIS]

Hacer algo a escondidas, parecer un santo, matarlas callando.
English?

[JPablo]

To play sneaky tricks; to do something behind somebody's back; to act or come over all virtuous; be a wolf in sheep’s clothing...

[Lorenzo]

Literalmente: To throw the stone and hide your hands.

Context: To be devilish or troublesome.

To be spiteful.

These could be translations to the meaning.