Just wondering what happens in a criminal case

[LifeonVenus]

Say there was a violent robbery.
You describe the robber as a white, one armed man.
You say that he spoke with an American accent and that he lived in Uxbridge let's say.

Would you expect police to put that information in and search for a similar suspect in previous cases? For reference, lets say you tell police that you got the impression that the robber had robbed before as he wore gloves and took other forensic measures.

Or, would it be more ususal for that not to happen and for police to call you 4 weeks later and say 'hey, we think we've got your robber in custody - will you make a statement now?'

Just wondering how this works.

In something as serious as a robbery then, yes, checks you describe would be made at the time.
If at the time of reporting the police thought there were very few reasonable enquiries to be made they wouldn’t always bother with a statement there and then if there was little hope of a detection. ( with low level crimes).
Different forces do different things though.

Say you didn't make a statement (official statement) after the robbery. Would you still expect them to run through a list of one armed white robbers from Uxbridge?
Why would they only contact you when they had him in custody for the exact same crime 4 weeks later?
Doesn't that mean that they knew who he was all along? Just didn't tell you?
Maybe because you didn't make the statement? But then why bother contacting you after the next crime?

Yes, basic intelligence checks should always be made.
Without knowing the full circumstances it may have taken 4 weeks to trace and locate him.
It could be down to poor time management or other reasons you may not know about.
They will now want to charge him with your offence as well as the new one.
Is it that the police didn’t want to take a statement at the time or that you didn’t want to?

Work will have been going on in those four weeks, but I think they’ve breached the victim’s code of practice (if you are the victim in this case) by not contacting you and giving you updates. They will have done a CCTV trawl around the location and gotten footage of the alleged offences. But without sufficient evidence to satisfy the Threshold Test, so that they have reasonable grounds for arrest and would be able to charge in custody, you can’t just arrest someone because a victim or witness described an unnamed suspects in a certain way.
They’ll have used that time to gather that evidence. Hope you are doing ok if you were the victim.

Also, the suspect would have been asked “are there any other crimes you have committed which you want us to take into consideration?”.
He may have admitted your offence or he may have been asked about your offence as they didn’t have enough evidence to arrest him for you offence.

Hey OP, how did it go with the hospital? I hope it was nothing serious.