Although there were a few saving graces of this episode, notably the guest performances, and Goren sitting at his desk playing with a circular saw ("be careful with that" warns Deakins, seeing the confirmed klutz too close for comfort, funny!), the plot was just too absurd to be plausible.
The storyline revolves around the construction troubles at an expensive high rise condominium. Pricey as the apartments are, foundation cement is giving off ghostly vapors, steam pipes interrupt your party with geyser displays, and rain storms tend to soak your carpets and hard woods, right through the windows. The murder at first appears to be an outgrowth of the developer's shenanigans..he favors some tenants over others and the folks who are upset they paid so highly for their poorly built rooms with a view are at odds with those few who are being bought off with better construction.
So initiallyt it looks like the detectives are faced with any number of suspects, and a credible denouement. However, a not very likely plot twist turns the story to one of sexual jealousy and a brainwashing that even a B sci-fi screenplay wouldn't touch.
The perp is a disheveled, weasely faced lover who met his paramour when she and her now dead hubby spent a few days at his and his wife's bed and breakfast. A tryst developed and the killer sold his B&B (evidently, his wife merely complied) in order to follow his girlfriend to the high rise condos, which of course, even without the construction issues, are priced beyond his means to begin with.
His lover (who eventually tells the detectives her dead hubby was a man but her boyfriend was a boy and strictly "for fun") continued the affair at the condos, altho she is so out of the weasel's league one wonders how much fun anyone could offer as compensation for physical repulsiveness. The killer, of course, wants lovely lady all to himself. He has found behind wall shafts that can be climbed straight up into his lover's closet (there is an amusing scene in which a detective planted night camera chronicles the "bug's" ascent to the honey).
But getting rid of the husband isn't executed in any easily believable way. He is killed from behind with a circular saw (which the detectives prove the nanny couldn't even operate), and the nanny herself has been brainwashed via text messages and photographs into believing God is telling her to rid the unfortunate building of corruptive influences.
Goren wants to know how God communicates with the nanny, and she is so vague (she doesn't hear voices, it's the post industrial age and the good lord speaks in tiny letters and images via your cell phone) that it becomes clear someone with an axe to grind with the victim has been posing as Jehovah.
When the poor girl realizes how pathological her susceptibility is (after all she is convinced she actually wielded the saw and there is no explanation of how the text messages could have given her such tactile memories), she moans "I'm so stupid." A compassionate Bobby (we know how he is with young people) comforts her with "You're not stupid to have faith". No it sure isn’t stupid to have faith , but this girl is dumb, Bobby, dumb. And as Eames sagely puts it 'it’s a big comedown from God's avenger to prize patsy".
The final scene in which the detectives pry loose the confession is amusing enough, as it includes a replay of the bug's ascent up his crawlspace ladder, but the disbelief suspender meter has to be set on 'overdrive' to get full value out of this one.
PS There was one element of the plot that could have been plumbed for some meaningful development, and that is the nanny's 9/11 trauma. The sight of the WTC's destruction fueled her delusion that God acts in mysteriously demolishing ways. One does wonder how many tenuous minds teetering on the edge actually were pushed over on that horrific day.