When a young girl goes missing, they try to find her. They find her dead. They try to find out who killed her. DNA on her body is matched to a man in CODIS. The man is not the killer but the killer's brother. They ask him who his brother is but he can't tell them because he doesn't know. It seems like he was adopted and he doesn't know who his biological father is. He knows who his mother is but has never met her. They go to see her and she says the father is a man she had an affair with who was married and he has two sons so they think it could be one of them. So they go check his sons but they are not a match. They learn that the father was with many women. And they eventually find a woman who has three sons and one of them could be the one. Dodds finds working the case a little unnerving.
Did You Know?
As Carisi is asking Lily's parents about her password, he asks about her cat's name...but it's impossible to input that on an iPad's numerical password screen (which is what appears when he shows her parents). Not a goof: the numbers on a password screen can be used the same as the letters on a telephone keypad. For instance, "cat" can be typed as "228" for a password (or "5459" for "Lily"). See more
[after Carisi lists all the evidence they have
Yeah, but don't know why
There's never a good answer to that question