Motive Episode 4.12 Chronology of Pain

After an explosion at a high-profile judge's home kills Angie's mentor, the team hunts for a sophisticated killer, who is an expert at covering their tracks.

Victim: Judge Natalie Rodman, Angie's former professor

Killer: Lexi Moore, Rodman's law clerk

The Discovery: Detectives Angie Flynn and Brian Lucas are called to an arson at Rodman's house, Rodman's grill exploded but she's seemingly unhurt. Angie runs into Mitch Kinecki, who worked his way out of Telephone Response and into the Arson unit and seems to be turning into a decent detective. They find the grill was rigged to explode. The judge is unconcerned and bosses her clerk, Lexi, to bring her work at home.

Rodman's husband Brent gives Angie the plate of a car that's been camped outside their house. It belongs to Craig Sugimoto, whose daughter was murdered last year. Judge Rodman sentenced her killer to just 12 years. Sugimoto says he followed Rodman to talk to her.

Angie re-interviews the judge about Sugimoto. As she's talking, Rodman starts to get lightheaded and gasps for air before passing out. She dies.

Later, Dr. Betty Rogers finds that after the grill explosion, Judge Rodman's lungs filled with fluid and over-inflated until they sort of exploded. Betty says doctors wouldn't have caught it even if she'd gone to the hospital.

Angie and Brian talk to the clerk at the judge's favorite store and he mentions delivering to her town house down the street. The location is news to them. Once they get there, they find Justin, her clerk boy toy. She spent three nights a week with him, Brent knew.

Brent says they had an open marriage and provides a list of both their lovers. The detectives don't think he knew about the town house.

Brian looks into the judge's finances while Angie tackles the affairs. None of the Rodmans' many lovers seem to hold a grudge.

Brian finds the town house was paid for with kickbacks from an eight-week boot camp for young offenders called Nature Bound and the judge sent a lot of offenders there - but the payments ended five years ago.

Background: Lexi is a hard worker, but the judge rode her to do more and didn't like when Lexi left work to run to her friend Meredith, when she called with a crisis.

Nature Bound was run by Mark Duff, an ex-con. He claims the judge was extorting him and wouldn't send kids there without incentive.

Brian talks to one of the former campers who Rodman sent there for the petty crime of throwing eggs off an overpass. Duff took him on a six hour night walk and smashed his knee when he couldn't keep going. He gives the detectives names of other former campers with whom he's trying to form a class action suit against Nature Bound, including Meredith.

Angie and Brian go to Meredith's house, where Lexi is inside cleaning in head to toe protective gear to cover her traces. She manages to leave without being noticed.

Inside the detectives find butane tanks and a funky smell. Meredith is dead in the bathtub, swaddled in towels and covered in roses and rock salt, cared for in death.

Dr. Betty Rogers rules it a suicide- she slit her own wrists. The rock salt makes it hard to pinpoint when she died, but it was before the judge was killed. She was bathed and dressed in fresh clothes. They realize Natalie was killed for revenge and head to Mark Duff.

Motive: Lexi and Meredith were childhood friends and were especially close after Lexi's mom died. Lexi tried to help Meredith cope with the after effects of her time at Nature Bound, which effectively ruined her life after she was sent there for stealing lipstick.

Lexi tracked down Duff and took her car to his garage. But Meredith got in the way of Lexi's revenge plans when she learned Lexi was working for the judge and felt betrayed, even though Lexi was just trying to gather evidence against her.

Knowing the cops are on her heels, Lexi stops by Duff's garage and clobbers him with a crowbar then lowers a car onto him, crushing him.

Then she disappears.

The detectives run down every connection to Meredith but find nothing but cat hair - even her cat is gone.

The Squad: Lucas freaks out when Sgt. Saunders says he wants to talk to him, but it turns out he wants Brian to apply for a position in Internal. Brian declines, but Angie thinks it's a smart career move. Then Brian admits to Saunders that he crossed a line recently and therefore doesn't think he's right for Internal. Saunders surprises him by saying that admitting his transgression is exactly why Brian would be a good fit - and why Oscar Vega recommended him. Brian is convinced.

After getting the blessing from her son, Angie has drinks with Oscar at her place and tells him she's planning to take the Interpol job in Paris. She doesn't feel right leaving the judge's case open but they have nothing more to go on. This one remains open.