<P> "Chicago Crossover" was seen by 10.01 million viewers making the second most viewed program of the night on NBC and the second ranked program in the time slot . Critical response to the SVU episode of the crossover was generally positive, many critics praising the tension - filled scenes and' fireworks' between lead actors Mariska Hargitay and Jason Beghe, who portrayed Sgts . Olivia Benson and Hank Voight, respectively; Lou Taylor Pucci was also praised for his portrayal of Teddy Courtney . </P> <P> The case opens up where the Chicago Fire episode "Nobody Touches Anything", left off; where the CFD firefighters rescued a man from a burning building and in his possession, he held a box full of child pornography, a box which was dropped during Lieutenant Kelly Severide's (Taylor Kinney) attempt to save the man's life . The CFD then turned this evidence over to the Chicago police . Detective Erin Lindsay has a personal stake in the case: her half - brother is involved somehow and in New York City . Benson gets a call from Voight that his team is on a plane to Manhattan to help the SVU solve the case . </P> <P> Lindsay explains to the SVU about how her half - brother Teddy Courtney (Lou Taylor Pucci) went missing when they were younger and how her mother thought that somehow he ran away to New York . Benson tells Lindsay that NCMEC ran Teddy's face through their system and they found more images, and concluded that he was connected to a pedophile ring . While searching for Teddy they learn from the National Center for Missing and Exploited Children that another young boy, Henry Thorne (Christian Godwin), is being victimized on a live stream, although at the time no one could track down where the feed originated from . They learn from the photos found in the Chicago fire that the ring is called the "Chess and Checkers Club" and it originated out of Chicago back in 2004; NCMEC pushing the federal government to shut down the website, but to no avail . </P> <P> Later the detectives discover through advanced facial recognition that Teddy has a juvenile record and went under the name Teddy Voight, who five years prior was arrested for solicitation . Lindsay explains to Detective Jay Halstead (Jesse Lee Soffer) that they knew Sgt . Voight before . SVU detectives Nick Amaro (Danny Pino) and Amanda Rollins (Kelli Giddish) go to a youth center where Teddy was remanded and learn that Teddy frequently ran away from the center . Security guard George Turner (Danny Mastrogiorgio) doesn't remember Teddy, but Miss Bagley (Donnetta Lavinia Grays) recommends that the detectives talk to Jocelyn Cerpaski (Isabel Shill), who left the center to start a better life . Jocelyn initially doesn't want to talk to the detectives, but she directs them to the piers where Teddy solicits . Rollins and Halstead find him and bring him in . </P>

Who plays erin lindsay's brother on chicago pd