Killer at the Crime Scene

I am a true crime fanatic. And I've watched hundreds of series, documentaries, and movies on the subject. If I had a top ten, killer at the crime scene would be in there. Very well made and presented series, that takes you from the evil deed right through to the capture and jailing of the perpetrator. Mainly crimes that happened in the UK. A lot around or in London. There are a lot of vile crimes shown here, perpetrated by the vilest people. Its always an unanswered question for me that how can one person do unspeakable things to another person. Yes, there's the motive, sex or money, their the big one's. Then there's the excuses, mental health, another big one. But I still don't understand it. Anyway, if you are fascinated by real life crime,I strongly recommend this series.