Matt Branson is the legal father of Patty Branson, who was assaulted by a biker passing by to try and kidnap her but only ended up pulling out her hair. Matt was horrified along with his wife Sarah that not only was Patty stalked and attacked the moment Matt was looking away and reading the newspaper, but the would-be kidnapper spoke with Patty before by showing her a dog.
The team responsible, private investigators Peter Carson and Kenny Pratt, Pratt being the one Patty interacted with, were both arrested outside Patty's school. They were hired by Michelle Osborne because she believed Patty was her dead daughter Anna. After Michelle was put on trial, a DNA test from Patty's hair revealed she was genetically related to Michelle, which explained why Anna's age progression photo resembled Patty.
After setting aside the assumption Matt and Sarah were kidnappers, when it was revealed both girls were conceived from in vitro fertilization, it was revealed the doctor, Stanley Norton, charged Michelle extra for her embryos to be retained by the clinic, forging the records to make it look like she consented. When mothers were unable to conceive, her embryos were placed into the other mothers' wombs, meaning Patty was one of Michelle's embryos with her dead husband Steve placed into Sarah's womb.
After Norton was arrested, Michelle personally kidnapped Patty on a class trip and was arrested again, refusing to let her obsession with Patty go even after the truth was revealed. Novak tried to get a conviction by placing Patty on the stand. When she started to cry and pleaded to stay with the family who raised her, Michelle was heartbroken and finally conceded to leaving Patty with her legal parents in their custody, taking a plea of custodial interference. Patty ran to her parents in tears, and after the trial was over, Michelle moved out of state while waiting out her suspended sentence.
Norton's records showed Patty had two sisters and a brother from Norton's other fertility procedures with Michele's embryos. (SVU: "Birthright")