Philadelphia Judge Genece Brinkley has denied rapper Meek Mill’s bid to overturn a decade-old conviction, saying there appeared to be a “lack of investigation” into claims that a key witness at Mill’s trial lacked credibility.

The embattled hip-hop star had been seeking to overturn his 2008 conviction on drug- and gun-related charges, but Brinkley issued a lengthy opinion Tuesday morning, saying Mill, whose real name is Robert Williams, failed to convince the court that newly discovered evidence raising credibility concerns about a key witness created enough doubt to warrant a new trial.