06E17 - Valhalla

Doyle finally makes direct contact with Prentiss, telling her that he will eventually kill her, but in the process, she is not to involve her BAU colleagues. Meanwhile, the BAU investigate two DC area house fires that occurred on the same evening. Both seem suspicious - one looking to be a murder/suicide, the other an accidental gas leak explosion - especially as they seem to be under-reported in the media. Upon further investigation, the suicide was not so (that person also murdered). The only seeming connection between the two sets of victims is a European background. When Morgan and Prentiss investigate a common contact telephone number between the two families, they are ambushed, and manage to kill one of their ambushers. It is then that Prentiss not only suspects but truly believes this is the work of Doyle. As the BAU further investigate, which includes why the one news story of the fires was pulled from its online posting, they do find a connection to Doyle. Through it all, Prentiss, still not saying a word to her BAU colleagues, works on both sides to find out where Doyle is and exactly what he is up to in his attempt to kill her in the meticulous fashion for which he is known.