Choose the right grammatical form in each gap to complete the text

When Sam [weren't coming|were coming|was coming|came]back home, he saw a car accident. Two cars [crash|crashed|was crashing|were crashing]at the pedestrian crossing. Sam was just about to cross it when he saw a red car. It [went|didn't go|were going|was going]too fast, and the driver didn't manage to stop. He hit a black car which was standing at the front. Luckily, nobody got hurt. The drivers called the police. When the police came, they started to question pedestrians and other drivers. Sam had to answer several questions too. While he was answering, the driver of the red car left the scene of the accident. The police quickly [found|find|was finding|were finding]the criminal and arrested him.