Place the crabs in hot water to kill them. It can be in the kitchen sink. You may also put the crabs in the freezer for about an hour. Pull of the back of the crab off and take out the insides. (Anything that is not white.) This can be done by shaking the crab over the garbage and the rinsing with running water. The meat should be left in the crabs. Remove the last joint on all the legs except the claws.
Squeeze the lemon over the cleaned crabs (open side up). Saute the bell pepper (and seeds), onion and garlic in 1/2 of the olive oil. When the bell pepper, onion and garlic are slightly tender add the tomato sauce, tomato puree and the bay leaves. Season with salt and lemon pepper to taste. Bring to a simmer and reduce heat. Once the sauce is simmering, add the crabs open side down. Cook on low to medium heat for about 20 minutes or until the crab legs are bright red.
Prepare spaghetti according to directions on package adding remainder of olive oil to water. Serve spaghetti and crabs with sauce over them.