The Lovely Bones

In 1973, 14-year-old Susie Salmon dreams about becoming a photographer. One day, Ray, a boy she has a crush on, approaches her at school and asks her out. As Susie walks home through a cornfield, she runs into her neighbor, George Harvey, who coaxes her into his underground den. Inside, Susie becomes uncomfortable and attempts to leave; when he grabs her, the scene fades until she is seen rushing past classmate Ruth Connors, apparently fleeing Harvey's den.
The Salmons become worried when Susie fails to return home from school. Her father, Jack, searches for her, while her mother, Abigail, waits for the police. In town, Susie sees Jack, but he does not respond to her when she calls. Susie runs home to find Harvey soaking in a bathtub. After seeing her bracelet hanging on the sink faucet near a bloody shaving razor, Susie realizes she never escaped the den and was murdered by Harvey. Screaming, she is pulled into the "In-Between", that is neither Heaven nor Earth. From there, Susie watches over her loved ones, unable to let go despite the urging of her new afterlife friend, Holly.
Investigating Susie's disappearance with Detective Fenerman, Jack thinks Susie was murdered by someone she knew. He researches neighbors and comes to think Harvey is the killer. Fenerman is unable to find any evidence pinpointing Harvey as a suspect, as Harvey cleaned up. Susie's sister, Lindsey, agrees with Jack's suspicions, but their casework takes a toll on Abigail, and Jack invites Abigail's alcoholic mother, Lynn, to move in with them. Feeling alienated from her husband, Abigail leaves for California. Susie, in her afterlife, learns that Harvey, who has now targeted Lindsey as his next victim, has murdered six other girls, including Holly, and that he stuffed Susie's body into a safe in his basement.
One night, Jack, carrying a bat, trails Harvey into the cornfield. However, Jack accidentally stumbles across Susie's friend, Clarissa. Her boyfriend, who mistakenly thinks his girlfriend is being assaulted, nearly bludgeons Jack to death as Harvey watches from a hiding spot. As Jack recuperates, Lindsey breaks into Harvey's house looking for evidence that he killed Susie. Upstairs, she finds a notebook containing a sketch of the den, a lock of Susie's hair, and news articles about Susie's disappearance. Harvey returns home and almost catches Lindsey in his house, but she escapes and rushes home to discover that her mother has returned. Not wishing to spoil her parents' reunion, she gives the book to her grandmother, who contacts the police. Harvey has already fled, having seen Lindsey running from his home â he takes the safe containing Susie's remains with him.
Susie's afterlife begins expanding into a larger heaven, and she is greeted by Harvey's other victimsânow showing nine, including Susie. She resists Holly's urging to enter Heaven along with the others, claiming she has one final thing to do. Meanwhile, Susie's classmates Ruth and Ray are present when Harvey drives up to dispose of the safe at a sinkhole dump site. Susie returns to Earth and enters Ruth's body, causing Ruth to faint. Ray rushes to Ruth's aid only to realize she has become Susie. They kiss, completing Susie's last wish, and she returns to Heaven as Harvey drives away. Meanwhile, the safe is seen tumbling down the sinkhole before disappearing into the muddy water.
Sometime later, Harvey meets a young woman outside a diner and offers her a ride, but she rejects him and leaves. A large icicle falls from an overhead branch, hitting Harvey on the shoulder. He loses his balance on the ice and falls backward over a cliff to his death. Time passes, and Susie sees that her family is healing, which Susie refers to as "the lovely bones" that grew around her absence. As the film concludes, Susie finally enters Heaven, telling the audience: "My name is Salmon, like the fish; first name Susie. I was 14 years old when I was murdered on December 6, 1973. I was here for a moment and then I was gone. I wish you all a long and happy life."

Question: Who does jack trail into the cornfield?
Answer: Harvey