At the top of the note, Mason writes two things. Each thing is a clue.

The first thing Mason writes is: "First, which of you animals is stinking up the staff room? It’s like you’re trying to mark your territory. You better move fast because I’m onto you."

The second thing is: "Second, while I get to the bottom of the stink, everyone else should relax. Grab a cold drink and a coaster (I left some in the cupboard) and give your brain a break."

Each clue corresponds to a number. You need two numbers to decrypt this note. If you want to know what type of cipher this is, read the next hint (if you don't want to know the cipher type, skip the next hint).

This note is encrypted using two Caesar ciphers. Once you figure out the two number, shift every first letter by the first number, and every second letter by the second number.

Pay attention to the words Mason underlined and read the Animal Fact Sheet ("Get to Know Our Animals") carefully.

Mason says someone is stinking up the staff room like they're "trying to mark their territory". Which animal does this?

The Animal Fact Sheet says lemurs engage in stink wars. The first clue is about lemurs. You need to find a number you can tie to this clue. Read what Mason wrote carefully, paying attention to the underlined words.

To figure out the second number, examine all physical evidence you received for Part 1 and read the Evidence Collection Form carefully.

For the first number—Mason underlined the word "fast". How fast are lemurs?

For the second number—Mason underlined the word "brain". He mentions leaving a coaster in the staff room. There is a coaster in evidence that was found in the Riverside staff room cupboard. Examine it carefully.

Lemurs' speed is 12mph. The first number is 12.

For the second number—there is an elephant on the coaster. Can you link elephant to a number based on what Mason underlined ("brain")? Check the Animal Fact Sheet.

This note is encrypted using two Caesar ciphers. The keys are 12 and 11. Every first letter is shifted by 12 and every second letter is shifted by 11.

The first key is 12 because in Mason's first hint, he says someone stunk up the staff room as if they were trying to mark their territory and that they better move fast. Lemurs engage in stink wars to mark their territory and move at a speed of 12 mph.

The second key is 11 because in Mason's second hint he tells staff to use a specific coaster and give their brain a break. The coaster has an elephant on it, and an elephant's brain weighs 11 pounds.

Decrypted, Mason's note reads as follows:

Last night, a piece of human trash dumped our beautiful Hannah. The night before her BIRTHDAY. I’m pulling something together last minute — please be in here by five PM so we can make her day suck a little less.

PS Calvin, if you’re reading this... just know Hannah told me everything you did to her the last two years. I kept my mouth shut for her sake, but all bets are off now. Oh, and don’t even THINK about showing up today. You’ll regret it.