Who is blamed for killing Agememnon?

Upon Agamemnon's return from Troy he was murdered (according to the fullest version of the oldest surviving account, Odyssey Book 11, l.409f.) by Aegisthus, the lover of his wife Clytemnestra. In old versions of the story: "The scene of the murder, when it is specified, is usually the house of Aegisthus, who has not taken up residence in Agamemnon's palace, and it involves an ambush and the deaths of Agamemnon's followers too".[1] In some later versions Clytemnestra herself does the killing, or they do it together, in his own home.