A cannibal and vampire have applied to be married just in time for Valentine's Day. Isakin Jonsson, 33, plans to marry Michelle Gustaffson, 23, behind the bars of their psychiatric hospital in Sweden. So what makes these two Sweden's most evil couple?

Jonsson was responsible for killing his girlfriend at the time, Helle Christensen. Christensen, a mother of five, had her head cut off by Jonsson. He then proceeded to eat parts of her body and boast about it on the internet. Gustaffson is no prize either. The Satan-worshipping vampire got her name by stabbing a single father to death and then drinking his blood. Gustaffson, like her future husband, then boasted about her kill by posing in a picture and posting it online. The picture featured her with blood dripping from her lips while holding a power saw and a knife. The caption of the picture read: I want to cut the throats of people on the subway.

The cannibal and vampire are inmates at a high security psychiatric facility, Karduddens. They are expected to remain in the facility for life, after opting for indefinite psychiatric over automatic life sentences. Jonsson and Gustaffson started dating on November 13th when Jonsson asked Gustaffson if she wanted to be his girlfriend though an internet messaging system. The killers got engaged on December 9th. According to the UK Daily Mail, experts believe that the couple will die in the facility because they are both so sick.

The vampire Gustaffson posted online this week that her and her fiancée, want to live together at some point, have dogs and pursue our hobbies: piercing and tattoos. The cannibal added, I love Michelle. Have never met anyone like her. I want to live a non-criminal life.

According to the UK Daily Mail, it is unsure whether justice authorities will grant their request to be married.

Jonsson and Gustaffson jailhouse marriage will be rare. They join other suspected murderers Marissa Star Bilotti and Iftekhar Murtaza, who got married behind bars in August 2011 in California. Bilotti, who faces 32 years to life in prison, was arrested for helping a friend murder a man. According to the Orange County District Attorney, Bilotti concealed a folded knife in her vagina while waiting in a getaway car. Murtaza was charged with two counts of murder and one count of attempted murder when he and two others were accused of killing the father and sister of his ex-girlfriend. He set their bodies on fire and slit the throat of his ex-girlfriend's mother.