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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Arkansas has become the first US state in 17 years to carry out back-to-back executions after putting two inmates to death.
Up to three million children risk going hungry over the school holidays, with increasing numbers of families relying on food banks, MPs say.
Tuesday will be a cold and windy day across the British Isles with a mix of sunshine and showers.