The investigation, code-named Operation Russell, allegedly raised questions about former commander Ray Adams's conduct before the Lawrence case, the Guardian said.
There was reportedly insufficient evidence to bring criminal charges and Adams told the newspaper this exonerates him and denied any wrongdoing.
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Through the day, most of the cloud should break up to leave fine conditions for many with spells of sunshine.
The Eiffel Tower in Paris was plunged into darkness, with the Burj Khalifa in Dubia emblazoned with the Union Jack.
The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.