Celtic Chronicles. Esther Brookstone Art Detective, #9

Esther and Bastiann volunteer to work at an archaeological dig near their modest castle outside Edinburgh. A student also working there is murdered. Police Scotland finds a Russian oligarch's number on the lad's call-list. That Russian is on his yacht anchored off the Scottish coast. As the investigation continues, everything becomes more complex, other characters come into play, and the intrigue and suspense increase.