This is not Carrie's sister Rachel it is Katrina, who was kidnapped by her step father who they thought might have been responsible for Rachels death. I have a picture from the end of "The Man in the Woods", but am not sure how to update the image.
Rachel Wells is the murdered older sister of main character Detective Carrie Wells and the daughter of Alice Wells. Carrie was there when her sister was murdered by an unknown person and she's the reason Carrie became a cop. The person who killed her was either named Johnathan or used the name as an alias. She has only appeared in flashbacks in Pilot and Lost Things (False. She appears in many episodes via flashbacks).
She is played by actress Haley Murphy.
The ‘Jonathan’ sketch image is later revealed to be the sketch of a ‘short term’ young policeman named Sam. Sam was on the Syracuse police force for the years circa 1983 at the time of Rachel’s murder. He carried Carrie’s childhood character to safety from the woods, sending her into a football game and safety of the crowd at the field. From there, Carrie flashes back to reveal she had seen the ‘suspicious RV with a rounded Pegasus character emblem’ which is alluded to as the murderer’s vehicle.
Sam aka Jonathan was not Rachel’s murderer but did not report the murder because he was in the woods attempting to receive a payment or drop from a criminal with whom he had been associated during his brief cop career. His career ended when he was ashamed he did not phone in the murder. He reveals that in the interim since 1983 he had tracked and surveyed murder scenes with similar details to Rachel’s. He bequeaths the research to Carrie after his death attempting to apprehend a suspect for a murder of a teen in Syracuse.
Sam reunites with Carrie after he is a suspect in the murder of a teen in Syracuse—Carrie is led to him by making a return call to a mysterious number on a cell phone that the force collected as part of the leads from the investigation into “Fred’s” background.