In a container suitable for marinating the meat whisk together the garlic, salt, pepper, vinegar, and wine.

Add the liver, onion, green pepper, and bay leaf to the marinade, cover, and refrigerate it for at least 1 hour.

In a large skillet, warm the oil over medium heat. Add the liver, and marinade and cook, stirring constantly, for about 10 minutes, or just until the liver is cooked on all sides.