You seem to have missed out the first part of the headline, Lass.
I will provide it for clarity.
Police couple who paid a deadly price chasing the middle-class lifestyle they couldn't afford: Guilty, inspector who strangled wife when she learned of his secret £54,000 loan to fund their gilded lives
She didn't die because of a middle-class lifestyle that they couldn't afford.
She died because he killed her.
He didn't pay a deadly price because he didn't die.