LAST EDITED ON Jan-30-04 AT 11:16 PM (EST)
 
It would be routine to track down all those keys and all the employees, but its a bit late now and most of those employees are transients or nearly so.

I would question the 'return on investment' of the manpower and time allocated to tracking down keys when there is such evidence of entry and exit via the window.

On-edit: In comparison, I would say the neighborhood canvass would be likely to be ore of a higher grade: it could turn up someone in the area. Such crimes are actually likely to be committed by people who are close by and familiar with the area, able to view the house without arousing suspicion, etc.

DA-Keenan undoubtedly knows the value of dna evidence but also realizes that without a suspect it is not worth much. Thats why they are probably going all through the ignored leads first. There is no use replowing an already well-plowed field. The "obvious suspects" such as LHP, Fleet White, The Groundskeeper, Jeff Merrick, McSanta are not likely to show up any differently the second time around. Someone who was overlooked the first time is more likely.