In 0 ABY, shortly after the destruction of the first Death Star, Rebel pilot Luke Skywalker survived an assassination attempt by X-7, an Imperial assassin working undercover among the Rebels. X-7 rigged Skywalker's speeder bike with explosives but the pilot was able to leap to safety at the last minute.
T'lin was tasked by the Alliance to investigate the assassination attempt, and he sent modified patrol droids programmed to detect traces of detonite. One of the droids found two kilograms of detonite in the smuggler Han Solo's temporary quarters in the Rebel base. T'lin confronted Solo about the evidence, and when the smuggler denied any wrongdoing, the lieutenant took him to custody. T'lin then reported his findings to Princess Leia Organa.