Somewhat inexplicably, evil always seems to find company. It's almost as if there's some kind of secret app that only the most messed up people use to communicate and congregate. Over the years, there have been some truly vile couples who have caused terror and distraught through their dagerous deeds. These are some of those killer couples.

1. Karla Homolka and Paul Bernardo

Possibly Canada's most notorious killer duo, this couple drugged Karla's 15-year-old sister, Tammy, and then strangled her to death. They also abducted and murdered two other teenage girls. While Paul is still in jail, Karla is free and lives under a new identity.

Source: All Thats Interesting

2. Ray And Faye Copeland

76-year-old Ray and 69-year-old Faye Copeland were convicted and given the death penalty in 1991 for the murders of 5 to 12 people. Through the 80s, the couple would give drifters fake checks to buy cattle from the nearby livestock market. When the cattle were delivered, they would kill the drifters and bury their bodies.

Source: Thoughtco

3. Charles Starkweather And Caril Ann Fugate 

If you've ever watched the film Natural Born Killers - these guys were the inspiration. In the 50s, 19-year-old Charles Starkweather and 14-year-old Caril Ann Fugate went on a killing spree, murdering 11 people in just 2 months. They were caught eventually, and Charles was hanged.

Source: NBC News

4. Gwendolyn Graham And Catherine May Wood

This lesbian couple worked as nurses, and were convicted of killing five elderly women in 1987. They committed their crimes in the Alpine Manor nursing home, and they were killing patients according to the letter of their first name so they could spell out 'MURDER'. By the time they were caught, they had managed to spell 'MURDE'.

Source: Medium

5. Fred And Rose West

This English couple would offer lifts to unsuspecting young women, then take them home and hold them captive, There, they would brutally torture them for days on end before killing them. Between 1967 and 1987, they committed at least 12 murders, and their home was known as the 'House of Horrors'.

Source: Independent

6. Ian Brady And Myra Hindley

Between July 1963 and October 1965, Ian Brady and Myra Hindley brutally tortured, sexually assaulted, and killed five children aged between 10 and 17 in the Manchester area. They would lure the young victims into the car before attacking them, and finally burying their bodies. They were both diagnosed as psychopaths.

Source: Birmingham Mail

7. Raymond Fernandez And Martha Beck

Between 1947 and 1949, Raymond Fernandez and Martha Beck are thought to have killed at least 20 people. They were a con artist couple who targeted lonely women, killed them and buried the bodies in their basement.

Source: Indiatimes

8. Carol M. Bundy And Doug Clark

This couple, also known as the 'Sunset Strip Killers', would lure bring prostitutes and runaways into their home. They would then kill them, and Doug would sometimes even have sex with the dead bodies. They even kept some of the body parts as trophies. 

Source: Rolling Stone

9. Charlene And Gerald Gallego

Between 1978 and 1980, Charlene And Gerald Gallego abducted and confined several teenage girls. Gerald would sexually assault them, and they would then be killed either by a gunshot or be bludgeoned to death. They were caught when a passersby witnessed one of the abductions.

Source: Mr and Mrs Murder

10. David And Catherine Birnie

This Australian killer couple would pick up teenage girls and take them back home. In 1986, they murdered 4 women, and tried to kill a 5th. The 5th would-be victim escaped and managed to tell the police, after which they were caught. The killing came to be known as the Moorhouse murders.

Source: Marie Claire

Double trouble never seemed so macabre.