Is it forbidden for a person to buy something through murabaha from the bank if the buyer pays a portion of the amount to the original owner of the car before the bank buys it?

This transaction involves a forbidden sale because it is a means to usury, as you sold your share of the car to the bank for an immediate price, then bought it back from the bank for a larger deferred price. This is what is known as the prohibited 'inah transaction. You are the real seller of your share because the rights of the contract revert to the principal. This transaction is considered a deception of the bank, and the Prophet, peace and blessings be upon him, said: "Do not commit what the Jews committed, lest you make lawful Allah's prohibitions through the slightest stratagems." Sharia standards consider this transaction void.