Accused Craigslist killer Philip Markoff crafted a ghoulish shrine to his former fiancée before killing himself in a Massachusetts jail, officials said yesterday.

Markoff spread pictures of Megan McAllister on a small table in his cell and then used a “primitive scalpel” to stab himself to death early Sunday, according to Suffolk County DA Daniel Conley, who called the suicide an “ultimate indicator of consciousness of guilt.”

Conley confirmed that Markoff wrote the words “Megan” and “pocket” on the door of his cell in his own blood, in an apparent tribute to McAllister.

It’s not known what the word “pocket” might have meant to Markoff or McAllister.

Markoff was accused of slaying Manhattan masseuse Juliisa Brisman, 26. She hooked up with Markoff on April 14, 2009, after he answered her ad in the erotic services section of Craigslist.

Surveillance footage outside Markoff’s cell showed he was alive until at least 1:59 a.m. Sunday.