DS9 Season 1 Episode 4 A Man Alone

Plot

Odo has become worried at the number of new people arriving at Deep Space Nine due to the newly discovered wormhole. While talking with Quark in his bar, Odo observes a man he recognizes and demands he leave the station. The man refuses and the two get into a fight that is broken up by station commander Benjamin Sisko. Odo explains to Sisko that the man is Ibudan, who was a smuggler of goods to Bajorans during the Cardassian Occupation. Though considered a hero by some, Odo states that Ibudan let a young girl die when her parents could not afford the smuggled goods, and later killed a Cardassian officer. He has since gone free after the end of the Occupation. Sisko warns Odo that he cannot take action against Ibudan without any evidence of a crime being committed.
Later, Ibudan is found dead in one of Quark's holosuites. One of Ibudan's friends reports to Sisko and Major Kira that Ibudan was afraid Odo would kill him. No DNA is found at the scene of Ibudan's murder other than that of Ibudan and the officers investigating the crime; the general populace of the station start to become suspicious of Odo, whom they consider untrustworthy due to his unknown origin as a shapeshifter and his past association with the Cardassian regime. Sisko temporarily relieves Odo of duty as head of security. Dr. Bashir discovers that Ibudan was performing medical experiments on a strange material in his quarters despite having no training as a doctor or scientist.
The crowds on the station become more hostile to Odo, who is forced to hide in his office to avoid a mob forming outside. Bashir suddenly arrives with new evidence: Ibudan's medical sample has started growing into a clone of Ibudan. Sisko, Bashir and Odo determine that the murdered Ibudan was also another clone, set up to incriminate Odo. They discover the real Ibudan hiding on the station, and Odo arrests him for the murder of his clone, but receives no apologies from the inhabitants of the station.
In a side plot, DS9's operations chief Miles O'Brien struggles to help his wife Keiko O'Brien get used to living on the station, where she is unable to follow her interests. She decides to start a school to teach the children residing on the station.