And the fraud should be punished by forcing the perp(s) to make full restitution and serve time as well.
The real problem is that in a high profile fake crime, assets are assigned to pursue red herrings and straw men, instead of doing other police work. It isn't just the expense, but the loss of effort devoted to other investigations, and the clock is ticking. Memories fading, witnesses deciding not to come forward, even degraded physical evidence can all happen while good investigators are tied up dealing with a high profile fraud.
That effect trickles down into the community, in the form of less police work getting done on real crimes.
So, add that intangible to any expense for the time and efforts expended on the fraud, then try to put a dollar amount on it and add it to their court costs and fines.