Scenes of someone drowning, it seems, followed by a bunch of cops taking a body out of the water. The body is badly decomposed. This is Yeats'  burial ground, according to Benson. Sonny thinks this is Yeats' work but this one was a floater, not buried like the rest. Benson thinks there may be a copycat killer.

The ME can't say for sure that Yeats did the crime but the injuries are consistent with the MO -- however the bodies were dismembered. Oh, but there is green nail polish.

Rollins interviews Yeats in jail. He says it's logical to think he was responsible. He says someone went out of their way to copy his crime. He doesn't know why someone would dismember the body. He looks at the photos and says Rollins has her work cut out for her. He may have some ideas in a few days.

Benson isn't convinced that Yeats isn't guilty. Rollins is totally convinced. Benson doesn't trust Rollins' judgment because she went to interview Yeats without permission.

Sonny discovers the victim was a college student, Brooke Groves, and had another life besides being a prostitute.

Fin catches up with Amanda at the vending machine. She says that she's tired because she's taking too many shifts since Nick left. But she's angry at how Benson is treating her, not at Nick leaving.

Benson and Sonny go to talk to the victim's mom. A woman  answers the door with two little kids and says she is Brooke Groves. Sonny tells her about the body. She says she has a twin sister that she is in touch with occasionally. Her husband banned her twin from the house because she had a drinking and drug problem. But Brooke sometimes talked to her, and a few months ago told her she was done enabling her.

Brooke goes to the ME's office to see the body. She is shocked by the decomposition but ID's the body right away. She throws herself on the M.E., crying.

Sonny goes to a shelter. The shelter worker is shocked she was killed. She says the woman left with an older woman that she assumed was her mother, in March or April. She gives a description and they go to look at the security footage. Their mother has been dead10 years, so Brooke doesn't know who it is. Also the time code is messed up as it says 2012 instead of 2014 and AM instead of PM.

Rollins says Yeats contacted her and only wants to give info to her. Benson won't let her go by herself.

Yeats is disappointed that Fin is there with Rollins. Rollins tells Yeats the victim had a twin. Yeats has a long shot idea. In 2002 an attending called him to give him stitches. The attending had bite marks on his inner thigh and scrotum. He claimed his partner was gone, but Yeats knew she was still in the house. Yeats could smell her fear. He doesn't want to give a name. However he gives a street address.

Benson and Fin come to the address Yeats gave them. The house has changed hands several times. They don't know who owned it in 2002. Rollins says the techs were able to pick up an image in the wall. There's a shadow. They get permission from the current owners to drill through the wall.

There is a suitcase in the wall. There is a mummified body inside.

Benson talks to Barba about it and updates him on the case. He thinks Yeats is guilty.

The ME says the body was dismembered just like the other body. Victim was about 25 years old, strangled, then skull fractured. Being wrapped in a blanket inside a chimney mummified her. There was no green nail polish this time. Victim was a redhead.

Rollins disagrees that Yeats is guilty. She walks off when Barba questions how he knew about the body.

Benson accompanies Rollins to interview Yeats again. Yeats says he knows who did it and who the victim is but won't talk unless he gets a conjugal visit with his fiancee. Barba agrees to it but warns Rollins she'd better be right.

The fiancee doesn't like it that she is asked to answer questions afterwards. The fiancee is convinced that Yeats is innocent and hopes that he will soon be released now that these new bodies have been found. She gives a name of the wall victim -- Lena.

Benson interviews Yeats. He is sleazy and acts like he's turned on by the idea of the woman being buried alive in the wall. The attending was a delicate man named Carl Rudnick. Benson says they're done. Rollins is angry. She says Carl Rudnick is the deputy chief ME in Manhattan. Yeats says Rudnick would get off on autopsying the bodies and would kill afterwards.

Rollins apologizes to Barba. But Sonny looked into it and Leah was real and did go to Columbia. Sonny says they have to look into this to rule it out so that Yeats can't get his conviction overturned. Barba agrees they should look into it.

Yeats' fiancee has photos of Lena and Carl with her and Yeats. She says Leah and Carl fought a lot. In 2002 Carl showed up at a party with a different date and said Lena was in Switzerland. Leah had told Yeats' fiancee that if anything ever happened to her, Carl did it. But she got a note from Lena and thought she was okay.

Rollins knows Yeats is guilty of the crimes he is already convincted of but doesn't think he killed the woman in the wall. Carl Rudnick was related to the owner of the house and was living there. Rudnick has said that the body in the wall can't be ID'd. 

Warner says Rudnick's time of death may be mistaken. Crabs did not eat at the body's tissue. She is surprised at the careless errors in Rudnick's reports because he is very meticulous. Benson can't tell Warner what this is about.

Fin tells Warner to watch her back with Rudnick.

Rollins shows Barba dental records that prove the body is Lena's. But the TSA says Lena left for Switzerland in early 2002 and there is no record of her returning. Rudnick came back from Paris around that time but no evidence he left the US. They think Rudnick dressed as a woman. Barba wants to call off getting permission to question Rudnick. Bring him on a pretext.

Barba says that this conversation is recorded, and that Yeats is trying to overturn his conviction.

Meanwhile Fin and Sonny search Rudnick's room and find autopsy photos.

Rudnick claims he didn't realize the body he autopsied was his ex. He claims Yeats was jealous of him.

Rudnick denies having anything to do with the murder and claims Yeats killed Lena to get back at him. Realizing he's under suspicion, he contacts his lawyer.

Benson and Barba agree that if Rudnick is convicted a lot of cases will be reopened.

After receiving a photo from Fin, Barba and Benson arrest Rudnick.

Rudnick pleads not guilty. Attorney requests ROR. Barba disagrees, saying Rudnick can flee and the crimes are heinous. Rudnick is given $2 million bail and must surrender his passport. He pays it immediately. 

There are already headlines about the case.

Benson is about to say goodbye to Noah when Rollins calls her over. Facial recognition is inconclusive, and Susie won't answer the phone. Yeats says something is wrong because Susie didn't call him. She had found the photo the night before. Yeats thinks Susie was killed.

Susie's home has been ransacked and there is dried blood on the walls. Freshly cut body parts have been discovered on the beach, according to a uniform.

An arm and leg have been found. Not sure it's Susie. Then they find a head.

Rudnick's lawyer stops the cops from searching Rudnick's home. She hasn't heard from Rudnick since he posted bail. 

Rollins pukes upon seeing the body.