Luigi Mangione

It sounds like they're buying time to find evidence that is admissable in court (ie not their illegal methods they used to first book the defendant while they try to scrounge together what they do need.)

So goes like this. You use illegal surveillance to track someone without a warrant. You arrest them and plant evidence as cause for lock up. Meanwhile now you can actually get a warrant to search the defendants computer, house, etc... To try to find something that does give you evidence of guilt that will actually be used to prove you think they're guilty.

Obviously he's innocent though.