A Corpse Tattoo is one of the memos that Heather Mason finds in Silent Hill 3. It is found on the arm of the corpse in the Examination room 3 on the 2nd floor of the Brookhaven Hospital. The memo holds a vital clue on how to open the Brookhaven Briefcase found on the same floor.
Ironically and tragically, Heather can find another tattoo on the body's leg that says, "Margaret, let's swear our love until death do us part."
The start time is my key.