Sunan Ibn Majah, Volume 3, Book 20, Hadith 2564 (DarusSalam) ⓘ
It was narrated from Ibn`Abbas that the Messenger of Allah said: “Whoever has intercourse with a Mahram relative, kill him; and whoever has intercourse with an animal, kill him, and kill the animal.”
حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ إِبْرَاهِيمَ الدِّمَشْقِيُّ، حَدَّثَنَا ابْنُ أَبِي فُدَيْكٍ، عَنْ إِبْرَاهِيمَ بْنِ إِسْمَاعِيلَ، عَنْ دَاوُدَ بْنِ الْحُصَيْنِ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ وَقَعَ عَلَى ذَاتِ مَحْرَمٍ فَاقْتُلُوهُ وَمَنْ وَقَعَ عَلَى بَهِيمَةٍ فَاقْتُلُوهُ وَاقْتُلُوا الْبَهِيمَةَ " .
also referenced under: Hadith 2564 (Reference) & Book 20, Hadith 2661 (In-Book)