This was a pretty good, if somewhat workman-like, episode, despite the fact that the writers are getting way too much in love with having super-unexpected twists at the ends of their stories. The story hangs together well, with the possible exception of how a certain character managed to throw a suitcase full of dead body out the window of a moving Amtrak train (do their windows even open?). Eric McCormack is excellent as a suspect who, for all of his other faults, is undeniably a truly loving father, and Christine Lahti is doing nicely on building her tougher-than-nails Assistant District Attorney character up as being wound just a tiny bit too tightly for the safety of herself or those around her; I'm expecting this side storyline to come to a head in two or three more episodes, preferably without her killing anybody.
But: I'm currently binge-watching L&O:SVU from the start, and after watching ten seasons in about three weeks I'm starting to get a subconscious feel, from the story or even just from the physical placement of the actors in a scene, for when they're about to pull something sudden and dramatic. In this episode I smelled the super-twist at the end about a minute before it happened; the only thing I got wrong was that I was expecting a letter-opener rather than a pair of scissors. Guys, you're starting to get predictable here.