Valmiki Ramayana Ayodhya Kanda Sarga 21 Shloka 32

पितुः father's, वचनकारिणा in obedience to the words, जामदग्न्येन by the son of Jamadagni, रामेण by Parasurama, जननी his mother, रेणुका Renuka, स्वयम् himself, अरण्ये in the forest, परशुना by an axe, कृत्ता was severed.

Parasurama, son of Jamadagni himself in obedience to the words of his father, decapitated his mother Renuka in the forest with an axe.