Someone else (not Jay), who was not involved in the murder/burial.
In an anonymous phone call on February 1, 1999 and/or February 12, 1999 advising the police to focus on Adnan, the voice on the phone sounded like an "Asian male 18-21 years old."
Police notes from Jay's third interview with the police on March 18, 1999 include a reference to a motorcycle for sale (“Mr. Brown” selling a Suzuki motorcycle, 600 CCs, with 9000 miles on it). Police then interviewed Karl Brown, the soccer coach at Woodlawn High, on March 23-24. Their pre-interview notes mention the Suzuki motorcycle that Brown had owned and sold.
Police notes from Jay's interview with the police on March 18, 1999 include the word "reward."
Discussion
Serial: Who killed Hae Min Lee?