LIKE many adopted children, Matthew Roberts set about finding his biological parents with a mix of nerves and excitement.
In particular, he hoped that discovering his father’s identity would help him to work out what made him the man he had become.
But nothing could have prepared him for being told his dad was… serial killer CHARLES MANSON.
Over a five-week period in the summer of 1969, Manson and his Family of commune followers committed a series of nine gruesome murders. Victims included pregnant actress Sharon Tate, wife of film director Roman Polanski.
Matthew, 41 - who bears a haunting resemblance to his father - sank into depression after discovering his identity.
He has since been in contact with his dad in a series of letters to his California prison and Manson has replied - each time chillingly signing off with a swastika.
Now Matthew, who was given up for adoption as a baby, has told of his horror at finding out he was the son of a monster.
He says: “I didn’t want to believe it. I was frightened and angry. It’s like finding out that Adolf Hitler is your father.
“I’m a peaceful person - trapped in the face of a monster.”
Matthew grew up in Rockford, Illinois, and didn’t know he was adopted until his sister told him when he was ten.
He loved his adoptive parents but always knew he was different. He says: “My parents were great people, but very conservative.
“They were products of the Fifties and I didn’t relate to them. My biological parents were products of the Sixties and I take on a lot more of those characteristics.”
He also reveals his adoptive father tried to discourage him from getting in contact with Manson, telling him: “Nothing good will come from this.”
Matthew, who now lives in Los Angeles, began investigating his family history 12 years ago when he contacted a social services agency who located his mother, Terry, in Wisconsin.
He wrote to her straight away and their early exchanges will be familiar to adopted children everywhere.
She confirmed she was his mum and told him she had named him Lawrence Alexander - and that she would tell him his last name in time.
The jigsaw of his life was beginning to take shape but it was still missing a crucial piece - his father.
Terry remained tight-lipped about his identity but after Matthew pressed her for details in a string of letters, she eventually revealed the awful truth.
She said she met commune leader Manson in 1967 - two years before the infamous “Manson Family” murders in Los Angeles for which he is still in jail at the age of 75.
But back in 1967, Terry had been one of many who were transfixed by Manson’s charms.
Her father had tried to chase him away when he met Terry, calling him a “white-trash biker bandit” but she found him charismatic and hypnotizing.
So she hopped on a bus with his Family and ended up in San Francisco. There she claims she was raped by Manson in a drug-fuelled orgy, after which she returned home and Matthew was born on March 22, 1968.
Terry always believed Manson was the father of the baby she gave up for adoption. And after seeing a picture of Matthew, her worst nightmare was confirmed.
For he is the spitting image of Manson, with the same nose, mouth, eyes and large forehead. They even have the same thick, arched eyebrows and long, thick, dark hair.
Like his father, Matthew is a songwriter and poet. He is even worried that he may have inherited his father’s schizophrenia.
Matthew, now working as a DJ, recalls hearing mum Terry’s bombshell: “She even said, ‘You look just like him’.
“I’m not nuts but I’ve got a little bit of it. It’s scary and upsetting. If I get worked up, my eyes get really big and that’s really freaked some people out before.