The Ironclad Alibi, by Michael Kilian (2002)

The Ironclad Alibi, by Michael Kilian, is a Harrison Raines Civil War mystery. It was published by Berkley Prime Crime in 2002.

Harrison Raines appears in the following mysteries:
A Killing at Ball's Bluff
Murder at Mabassas
A Grave at Glorieta

Here's the backmatter for The Ironclad Alibi

U.S. Federal Agent Harrison Raines' latest mission is to investigate "The Monster" - the Confederate Navy's first ironclad ship - in his old home town of Richmond, Virginia. Through a chance encounter with his first love, Bella Mills, Harry learns that her husband is in charge of the ship's restoration. But when Bella is murdered, Harry's friend, ex-slave Caesar Augustus, is arrested for the crime. Now Harry must find the real killer, rescue Caesar, and inform the Union about the new Confederate menace.