Who is at fault Vehicle 1 or 2?

Based on the provided information, it seems Vehicle 1 may be at fault. Vehicle 1 entered the roundabout from the outside left lane into the right lane, crossing paths with Vehicle 2 which was traveling to its left (also from the left lane).

According to general driving rules, when entering a roundabout drivers usually give way to traffic to their right as a general guide of right of way inside the circulatory system. While the rules may vary depending on specific traffic regulations in your city, the driver of Vehicle 1 may bear significant responsibility as their driving action (moving diagonally while turning left) disrupted a vehicle from an adjoining lane (Vehicle 2).