The Twelfth Card

from the constables—who now search everywhere for me,—and in the morning, I will steal to New Jersey. You and ourson must flee too; I fear they will try to visit their vengeance upon you, as well. Tomorrow at noontime meet me at the John Stevens Pier in New Jersey. Together, we will repair to Pennsylvania, if your sister and her husband will agree to harbor us.
    “ ‘There is a man who lives in the building above the stable where I am now hiding, who seems not unsympathetic to my plight. He has assured me he will get you this message.’ ”
    Sachs looked up. “Something’s crossed out here. I can’t make it out. Then he goes on: ‘It is dark now. I am hungry and tired, as tested as Job. And yet the source of my tears—the stains you see on this paper, my darling,—are not from pain but from regret for the misery I have visited upon us. All because of my d——ed secret! Had I shouted the truth from the top of City Hall, perhaps these sorrowful events would not have transpired. Now it is too late for the truth. Please forgive my selfishness, and the destruction wrought by my deceit.’ ”
    Sachs looked up. “He signs it only ‘Charles.’ ”
    The next morning, Rhyme recalled, came the pursuit and arrest described in the magazine Geneva had been reading when she was attacked.
    “His one hope? ‘Hidden beneath clay and soil.’ ” Rhyme looked over the letter again, Sachs holding it up for him. “Nothing specific about the secret . . . And what happened in Potters’ Field? That’s the pauper’s graveyard, isn’t it?”
    Cooper went online and browsed for a few moments. He reported that the city cemetery for indigents was located on Hart’s Island, near the Bronx. The island had been a military base, and the graveyard had just opened on it shortly before Charles went there on his mysterious mission, armed with his Colt pistol.
    “Military?” Rhyme asked, frowning. Something had clicked in his memory. “Show me the other letters.”
    Cooper produced them.
    “Look, Charles’s division was mustered there. Wonder if that’s the connection. Anything else about the graveyard?”
    Cooper read. “No. There were only two or three hits.”
    Rhyme scanned the white board. “What the hell was Charles up to? Gallows Heights, Potters’ Field, Frederick Douglass, civil rights leaders, congressmen, politicians, the Fourteenth Amendment . . . What ties them all together?” After a lengthy silence the criminalist said, “Let’s call in an expert.”
    “Who’s more expert that you, Lincoln?”
    “I don’t mean forensic science, Mel,” Rhyme said. “I’m speaking of history. There are a few subjects I’m not proficient in.”

Chapter Twenty-Two
    Professor Richard Taub Mathers was lean and tall, with skin dark as mahogany, sharp eyes and an intellect that suggested several post-graduate degrees were tucked into his résumé. He sported a throwback short Afro hairstyle and a self-effacing manner. He was dressed, well, professorially: tweed jacket and bow tie (missing only the de rigueur suede elbow patches).
    He nodded to Rhyme, with a brief double-take at the wheelchair, and shook hands with the rest of those present.
    Rhyme occasionally lectured at local colleges on forensic science, mostly at John Jay and Fordham; he rarely appeared at such lofty venues as Columbia, but a professor he knew at George Washington down in D.C. had put him in touch with Mathers, who was, it seemed, an institution unto himself in Morningside Heights. He was a professor in the law school—teaching criminal, constitutional and civil rights law as well as various esoteric graduate courses—and lectured in African-American studies in the undergrad program.
    Mathers listened attentively as Rhyme related what they knew about Charles Singleton and the civil rights movement, his secret, how it was possible that he’d been framed for robbery. Then he told the professor what had happened to Geneva over the past two days.
    The professor blinked in shock at this news. “Tried to kill you?” he whispered.
    Geneva said nothing. Holding his eye, she gave a faint nod.
    Rhyme said to Sachs, “Show him what we have so far. The letters.”
    Mathers unbuttoned his jacket and pulled on thin, stylish glasses. He read Charles Singleton’s correspondence carefully, unhurried. He nodded once or twice, gave one faint smile. When he was finished he looked over them again. “Fascinating man. A freedman, farmer, served in