The Twelfth Card — Jeffery Deaver

Schoolgirl Geneva Settle's research project into her slave ancestor Charles Singleton unearths more than just an interesting story. Suddenly Geneva seems to be the target of a professional assassin. A man who will ruthlessly kill anyone in his way unless top crminologist Lincoln Rhyme can piece together the deadly puzzle.
Trapped inside a paralysed body, Rhyme's brilliant mind is channelled through his partner, policewoman Amelia Sachs, as they work frantically to anticipate where the hitman will strike next, and how to stop him.
And Rhyme and Sachs soon realise the only way to stop the killer is to discover the secret Charles Singleton took to his grave over 140 years ago - a secret that threatens to destroy the future of human rights itself.