User blog comment:HTFan/What is the reason for Mr. Pickles' murders?/@comment-26365046-20150908140036/@comment-26245895-20150908145037

That is very reasonable, since the other episodes featuring Lammy she was directly interacting with others, thus making Mr. Pickles jealous. And as Adam said, Mr. Pickles could have killed Lumpy off-screen. However, this could also bring up the argument that Mr. Pickles is nothing more than the imagination or Lammy, thus, upon her death, he 'died' with her.