The Matrix is, more than our Internet, a series of interconnected machines. SINs are backed up pretty much globally, so erasing someone from the system requires you hack into about thirty to fifty machines, not setting off any alarms, and not only erase the data, but tear down certain protocols and tags that cause the system to forward the data. Within an hour. Some will still have forwarded it before being erased, so you'll have to triple-check after you've finished.
KE is going to have about a dozen machines, maybe more, that any serious crime would be forwarded to within seconds, by an automated process. One for this branch, one for a record, one for an APB, one to the facial recognition database, and etc. Some will frequently offload data to LAN drives. (Local Area Network, hardwired to only that machine, and untouchable without physically hacking the backup machine, because it's offline.) How frequently? I would say no more than ten minute intervals, maybe less in between.
You destroyed the main copy? That's freaking great. Go after the extras. The drone has it on file, and probably does a hard data-dump when it docks from its shift for maintenance. If they've already sent out Investigators, (half hour, TOPS, since most of the system for this is automated) then even if the agents assigned to the case aren't able to move onto the case yet, from backlog, they have the details on their own Links.
"Huh. I went to reference the timeframe 'x' to 'y', and it turned up totally blank."
"We've been hacked!"
If data goes missing, from a KE database, and in a stupidly obvious way, (If he didn't use Spoof, for example, to replace the data, then he left a black hole of data, which implicates him as well as the real perpetrator) they will gladly send in every scrap of firepower they can - they take stupid shit like that seriously, like an act of war. They may not have access to Submerged Technos, but higher up on the corporate ladder, someone does, and if the party has been operating hot in the area for a while, interrupting the corp's operations, then they'll send someone in to the Great Library, which is where deleted data goes. Resonance never forgets.
So, now they /think/ they're free. But instead, they have a pissed off corp, a bunch of investigators on their tails, they haven't expunged any records, and KE is going to shoot first, and interrogate their corpses. Congratz, guys.
Guy thinks he can fast-talk his way out of trouble, it sounds like. Turn the tables, let his actions rebound will emphasis.