Speaking to MPs on the Home Affairs Select Committee, Doreen Lawrence said she had no confidence in the police and added it was not right for "police officers to investigate each other".
I have no confidence whatsoever.
Over the years, I was beginning to have a level of trust, we had the investigation and the court case... I was beginning to have some confidence. Now I just don't know what to believe anymore."
You can't have police officers investigating each other. It's proven that's not the right way to do things.
More top news
Mr Kim has made two recent visits to China.
The study looked at the development of 422 children over the course of eight years.
The president said they will come into force if China refuses to change its practices.