It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Kill both the active and the passive partner who commit the act of the people of Lut, and also the one who commits bestiality with an animal, and also the one who commits fornication with a woman who is his mahram."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11520