[Is It Permissible to Buy a Car from Highway Robbers?]

Answer: This is not permissible in the religion of Islam and is unlawful. The usurped car remains the property of its owner; whoever buys it from the usurper has squandered his wealth and involved himself in the crime of usurpation, sharing with the usurper in taking others’ property without right. Thus the purchaser has lost lawful wealth and exchanged it for unlawful wealth—“He has lost [this] world and the Hereafter; that is the manifest loss.” [Al-Hajj:11]
Moreover, an objector may argue: “There is no harm upon me in what I did, for I purchased the car lawfully; I did not perpetrate the highway robbery nor the usurpation.”
We reply to them: There is no doubt that Allah, Exalted is He, has forbidden the wealth of Muslims to one another, except what the owner is content to give by sale, gift, vow, charity, etc. In the hadith [of the Farewell Sermon] it came: “Indeed, your blood and your wealth are sacred to you like the sanctity of this day of yours…” to the end of the famous sermon. And Allah, Most High, said: “O you who have believed, do not consume one another’s wealth unjustly but only [in lawful] business by mutual consent from among you.” [An-Nisā’:29] And He, Most High, said: “Indeed, Allah commands you to render trusts to whom they are due…” [An-Nisā’:58].
Therefore, the highwayman who seized the car has sold what he does not own, and the purchaser has bought from other than the owner of the car. Thus the one who buys the car from the usurper has taken and purchased what Allah and His Messenger—May Allah bless him and his family and grant them peace—have prohibited in the Book and the Sunnah.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2