Anthobium unicolor - a rove beetle

Found on dead wood in the woods while seeking corticioid fungi, this rove beetle appeared in my collecting box, so I figured I might as well try to identify it anyway. It turned out to be Anthobium unicolor Thanks for assistance go to RW and GC. If I could identify its passenger I could get two ticks for the price of one. Or three for two since I already recorded the Kretzschmaria fungus (not corticioid!)