When receiving a law enforcement request for supporting documentation on a SAR by phone, what are other banks requiring in order to verify that it is a legitimate request from the law enforcement agency? They did not come in person.

They don't need to be present to make the request, but most of the banks I've dealt with would require them to pick up the documents "in person" and show their LEA credentials upon delivery. Some banks also require a letter from the agency indicating the person is authorized to pick up the documents.

The fact that your bank need not require a subpoena does not suggest that you can mail, e-mail, or fax customer information based on a phone call. They're not ordering a pizza...

I would askthat the request be sent on their department letterhead and then call to verify that the individual requesting the documentation is employed by the department.

I would also require that the requester include the DCN (document control number(s) of the SAR(s) he/she is referencing.