I KNOW WHAT YOU DID LAST SUMMER THE SERIES (PILOT)

The note. That awful note. That's what started this all

When Destinee Ybarra gets a note in the mail she receives an ominous threat, "I Know What You Did Last Summer." She asks anybody who sent the note, but no one seems to knows. That's when Destinee starts to follow this psycho. Who did this? And how does he know?