Partial answer for note 2 (?):

The second letter of each sentence is lkmuypp which with a Caesar shift of 16 becomes backoff.

Answer:

In your own attic.

Note 1:

The word "first" tells us to take the first letter of each sentence. These say ETTUBRUTE which indicates a Caesar cipher. (Thanks to @Rubio for solving this part.)

Note 2:

The second letter of each sentence is lkmuypp which with a Caesar shift of 16 becomes backoff.

Note 3:

Dropping the last letter of each line (taking the "back off") gives wbhvsrshsqhwjsgohhwq which rot-12s to inthedetectivesattic.