STANDARD DISCLAIMERS APPLY: You are not my lawyer, I am not your client, this is all hypothetical, blah blah blah.
On August 1st I am found guilty of a crime; say, check fraud. The sentencing date is set for September 15th. On August 2nd I am charged with murder and taken to jail; unable to make bail, I sit in jail for the duration of the murder trial. September 15th comes: I am sentenced to 364 days in jail.
Since I’m already in jail (albeit on an unrelated matter) when sentenced* to *jail, do I get any credit for my check-fraud sentence while sitting in jail awaiting my murder verdict? Does it matter if I am ultimately acquitted of the murder charge?
This will depend completely on the state you are in the relevant statutes and case law.
Most states would not grant you jail credit to your fraud charge for the time served awaiting the murder trial, unless you the two crimes were closely linked (even then, again, depends on state law).
Once you are sentenced in the fraud case, you would probably begin serving time for that case. If you are ultimately acquitted of murder charges, you’re talking a trial which would probably be several years in the future. At that time you would have already served your jail time for the fraud.
If you are found guilty of the murder, the time served for the fraud case will probably not be able to be counted as credit against your sentence in the murder case.
As a general principle, this is a matter almost entirely at the discretion of the sentencing judge. I know of no reason he or she would be required to credit your time awaiting trial to your check charge, and no reason he or she could not do so if desired. Obviously, some states may have mandatory sentencing requirements that change those answers.