Murder on the Potomac by Truman, Margaret - 1995

"In her tenth Capital Crimes mystery, Margaret Truman has brought back the attractive couple Annabel and Mac Smith. Both are ex-lawyers - Mac now a legendary professor, Annabel the owner of a prospering Georgetown art gallery. When Mac is called in on yet one more murder, Annabel's patience is strained again. And when the middle-aged Mac encounters a smart, stunning female former student, now a detective, Annabel's joy is extremely contained.
"The weed-covered body discovered on the Potomac riverbank draws them into several overlapping circles: the Scarlet Sin Society, a theatrical group that reenacts murders from Washington's rich history, sometimes at the risk of murdering one another; the intrigues in and around the National Building Museum, whose board is presided over by a wealthy D.C. developer; and locales as diverse as Chinatown, Atlantic City, and the Bahamas. And all of this over Annabel's almost-dead body. "; 6¾" - 7¾" Tall .