This is obtained during the Nicholson's Electroplating case.
After obtaining the deciphered address at the blast site you will want to head there.
When you arrive at the address you will notice it's an apartment. Here are the clues you will want to obtain in order to unlock the achievement.
-Look at the mailboxes to find the apartment number.
-Inspect the refrigerator.
-Look at the body. Inspect the head and both arms. You will see a wristwatch and a ring.
-There is an LAPD tie clip in front of the fireplace.
-The far corner of the bedroom as you enter you should see a shelf, there is an earring there to inspect.
Get all these and the achievement is yours.