Besides the whole 'the existence of this kind of crazy is a highly classified government secret' deal? [She's already going to be in a metric ton of trouble when she gets back, so she might as well explain it all.]
The painting was lost. It's been locked in some hermit's basement in Poland for the past forever, 'til the police confiscated it when said hermit's daughter got to Lizzie Borden-ing. Cops there just thought they were dealing with a serial killer, and then the same thing happened last week with the art dealer who sold the painting. It takes a while for the mutilating urge to kick in. Nobody really made the connection. [She shrugs.] Happens all the time with artifacts.