The 5th episode of the third season introduces us to Calvin Mantus.
Calvin Mantus grow up in Whitechapel however he murdered his parents and 10 year old sister when he was 20 years old in 2001. Mantus murdered his family at their Sunday lunch and sat them back in their chairs around the table whilst he finished his food. Apparently he wanted to eat his meal in silence. He was arrested, but was judged unfit to stand trial as he was clinically insane. He was then put in Broughton psychiatric hospital.
Calvin escapes the psychiatric hospital at age 30 and DI Chandler and the team get an alert informing them of his escape. Not long after this alert there is a murder who's body appears to have been staged/positioned leading Chandler and the team to have Calvin as a suspect.
The Mantus family house was never sold, never used by drug addicts and nobody squatted in their house either. This was because the locals say it's haunted by the ghost of Daisy Mantus who runs around at night screaming.
Mantus requires silence this is why it is surmised he murdered his family, so he could eat his meal in peace. The irony of his being locked in a secure unit full of activity and noise for killing his family is not lost on his Doctor. He loves silent movies, in particular “London after Midnight” starring Lon Chaney. He claims to have the only surviving copy of the film.