Unusual cat death need necropsy, how to get one?

yesterday my heathly 7 yr old cat died suddenly. my hubby was sitting on the back porch & yelled in to me, " zinger is pooping, he'll probably be in in a minute." sure enough after vigorusly covering his waste he came bounding in as he always does, laid down half under the kitchen chair, as he always does.he moaned a few times like he had a belly ache & wanted to throw up. my hubby said, "when i come in i'll take him out so he dosn't throw up while we're eating." i was puting food on the table & ped him a few times, his tail was fluffed like he was afraid & his mouth slightly open. hubby said, "ok zing time to go out", & gave him a little push with his foot. he didn't move & we knew he was dead. i've had cats all my life, had them go away to die & had to euthinize them them at the vets but never did i see this sort of thing happen so suddenly. with the tainted cat food scare i was concerned for my other 5 cats but all zinger ate is crunches. ( see next comment, continued.)