Heat oil and butter in a large saucepan over medium heat.
Saute onion and garlic until onion is tender and translucent. Stir in crushed tomatoes, diced tomatoes and sun-dried tomatoes. Simmer 5 minutes on medium heat.
Add peppers, black olives, green olives and capers. Simmer 15 to 20 minutes on low heat, or until sauce has thickened.