What is the ruling on purchasing a plot of land in the countryside, and does one absolve himself of responsibility by doing so, given that the project established on it has been completed and citizens have acquired ownership of it from the state after submitting the necessary documents, but there are rumors that the land previously belonged to other people?

It is permissible to purchase land that has been expropriated from its owners if the expropriation was due to a legitimate, recognized Sharia reason and the owners were adequately compensated. However, if the expropriation was without a legitimate Sharia reason, or without compensation, then it is not permissible to purchase it from the one who possesses it, because he does not own it. This would constitute cooperation in sin and unlawful consumption of people's property, in accordance with the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression," and His saying: "And do not consume one another's property unlawfully." What is mentioned above is based on the strong presumption of the information's authenticity; mere doubt does not prohibit what is permissible.