Jake Keegan is the husband of Leah Keegan, who had a son named Tommy. Jake was first found when Tommy ran through the streets covered in blood and Jake came to retrieve him, worrying the blood was Leah's. It wasn't, and Tommy's nanny, Jodi Simmons, was found dead in the Keegan home.
After Jodi's killer was arrested, Jake overheard Tommy was not his biological son, but that of Leah's lover Matt Kramer from Stabler. He was devastated and even made Stabler question his own youngest baby. Jake attacked Matt when he showed up at the house to meet Tommy, leading to both men's brief arrests. Once released, Jake was horrified he was Tommy's legal father and still had to pay support for him despite his plans for him and Leah to divorce.
Jake left Tommy at the precinct to be in Matt's custody after killing Leah and running off to his log cabin. Before he could kill himself, he was restrained by state troopers and arrested after telling Stabler why he killed Leah. (SVU: "Paternity")