I know that multiple threads discuss similar situations but I am currently at a loss to find the correct solution.

I am trying to update a table and related subform (tblEvidenceItems) that tracks Computer Security incidents which includes the tracking of evidence items.

What I need to do is automatically create an incremental number for each piece of evidence based on the IncidentID.

For example:

If IncidentID 07-0067 has 6 pieces of evidence, I would have to show Item 001, Item 002, ... Item 006, etc.

If the next IncidentID has 12 pieces of evidence, I need to show Item 001, Item 002, ... Item 012.

The fieldname for the Evidence Items in tblEvidenceItems is ItemDetailNo.

Can anyone provide me with some assistance??