The 87th Passenger Part 2

She opened the note. It read: 

"3 1 12 9 6 15 18 14 9 1"

Luna raised an eyebrow. "What can this mean?" "A puzzle!" Nancy exclaimed. "We have to solve it." Luna studied the finger prints on the note. Surprisingly, the person had left no fingerprint. It was blank on the other side. Not a single fold, the note looked new. "Doe that mean that the person wrote this note just a few minutes ago? That's a huge clue!" Nancy said. Luna nodded, saying nothing, as she kept staring suspiciously at the note.

Suddenly, someone shouted. "WHAT IS THIS?"

Loud chatters were heard from the investigation area. "What's the matter?" Luna said. Both rushed out of the plane. "What happened?" Nancy asked an air hostess who was passing by. Sweating, she replied, "Someone stole 1 billion dollars from the California bank 2 minutes ago"