TOKYO - A former member of an elite investigative unit of Tokyo prosecutors has become the target of a probe for allegedly having an improper relationship with a woman he had questioned in connection with a case, sources familiar with the investigation said Wednesday.

The 48-year-old prosecutor, who was until last year part of a team that investigates corruption among politicians and financial irregularities at corporations, had led a probe into the recent slush fund scandal involving the ruling Liberal Democratic Party.

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