A couple decided to take a DNA test to find out more about their family history - and uncovered a dark secret.

Bizarre on Female First

Bizarre on Female First

The 27-year-old woman dumped her partner when she discovered the 26 year old was related to an ''infamous serial killer''.

The unnamed man posted on Reddit: ''A month ago my girlfriend and I thought it would be fun to do the DNA test offered by Ancestry.com to learn more about our family tree.

''They really give you a lot of info and it took a while to go over.

''We were having a lot of fun with it but then I found something out about one of my ancestors that has now caused me to lose my girlfriend.

''There were a few names in my family tree that I did not recognise and after doing some research it turns out that one of my ancestors was an infamous serial killer.''

Finding out the news, his girlfriend broke up with him and now he is desperate to win her back.