IV. Ysidro, a paying passenger, was on board Bus No. 904 owned and operated by Yatco Transportation Company (Yatco). He boarded the bus at Munoz, Nueva Ecija with Manila as his final destination. He was seated on the first row, window seat on the left side of the bus. As the bus was negotiating the national highway in front of the public market of Gerona, Tarlac, the bus came to a full stop because of the traffic. The driver of the bus took this opportunity to check on the tires of the bus and to relieve himself. As he was alighting from the bus to do these, an unidentified man standing along the highway hurled a huge rock at the left side of the bus and hit Ysidro between his eyes. He lost consciousness and immediately the driver, with the conductor, drove the bus to bring him to the nearest hospital. He expired before the bus could reach the hospital. Ysidro's wife and children brought a civil action to collect damages from Yatco, alleging that as a common carrier, it was required to exercise extraordinary diligence in ensuring the safety of its passengers. They contended that, in case of injuries and/or death on the part of any of its passengers, the common carrier is presumed to be at fault. In its defense, Yatco alleged that it is not an absolute insurer of its passengers and that Ysidro's death was not due to any defect in the means of transport or method of transporting passengers, or the negligent acts of its employees. Since the accident was due to the fault of a stranger over whom the common carrier had no control, or of which it did not have any prior knowledge to be able to prevent it, the cause of Ysidro's death should be considered a fortuitous event and not the liability of the common carrier.