Watch Look Out, Officer! 1990

After police officer Piao is murdered, his soul cannot be at rest for his murder has been written off as a suicide. Therefore the heavens send him back to Earth as a spirit to find his 'savior' who will help him clear his name. Hsing, a rookie officer, is the savior and in return for finding Piao's killer, Piao must get him a girlfriend and a promotion.