Murder Room / P.D. James 653 p.

Commander Adam Dalgliesh returns for the 12th in the series to investigate murder at the Dupayne Museum, a small private museum in London focused on the time between World War I and World War II.  Museum owners and siblings are divided as to the fate of the museum.  Dr. Neville Dupayne is murdered at the museum in a way that resembles a case on exhibit at the museum.  Everyone at the Dupayne is explored.  Another murder occurs paralleling another historic murder case at the museum.  P.D. James builds characters with quirks and dept, leads to reader down the wrong path, and continues Dalgliesch's love interest in this police procedural.