Police Diary (1988)

This fast-paced revenge thriller follows the trials and triumphs in the life of two brave and honest police officers, Pandian and Arun. Arun's sister Pallavi is a drug addict, who is unable to give up her self-destructive habit despite Arun's plodding and pleading. In a fit of vexation, Arun locks her up one day to ensure that she cannot buy any more drugs, but she ends up dying from withdrawal. Devastated and ridden with guilt, Arun decides to take revenge on Mohandas, the kingpin of drug mafia, but Mohandas kills him in an airport restroom. This terrifying incident is witnessed by Sudha's young brother, but the young man is too terrified to publicly expose the crime. Pandian, who is the officer in charge of investigating the case, zeroes in Sudha and her brother as witnesses, but she refuses to cooperate. However, she is later pleaded with and convinced to help the police nab the criminal responsible for this terrible crime. Despite all their efforts, the investigation comes to a grinding halt when Pandian himself is abducted by Mohandas's men and forcefully turned into a drug addict. Will Pandian have the strength of will to defeat the powerful chemicals taking over his body, and successfully avenge the death of his friend, by putting an end to the drug lord's criminal network?