In a large skillet over medium heat, add the ground beef. Cook until browned, breaking it up with a spoon. Drain any excess fat.

Add the chopped onion and diced red bell pepper to the skillet with the beef. Cook for about 5 minutes, until the vegetables start to soften. Stir in the minced garlic and cook for another minute.

Move the beef and vegetable mixture to a slow cooker. Add the diced tomatoes, tomato sauce, olives, and capers.

Sprinkle in the cumin, garlic powder, salt, and black pepper. Mix everything well to combine. Place the bay leaves on top of the mixture.

Cover the slow cooker and cook on low for 6-8 hours, or on high for 3-4 hours.