Stegosaurus? Maniraptors? Pachycephalosaurus? (just some wild guesses)
It will be obvious when you get the right dinosaur.
This is exactly how it unfolded:
The man is barely breathing, but he tries to say something:
"The . . . errgh . . . diamond . . . is . . . oh no . . . I am dying . . . sorry . . . e-e-erh . . . "
Seemingly unable to speak, he stretched his hand and wrote on the grown using his own blood:
S-P-I-Nbut he lacked strength to continue. The woman put his ear close to his mouth and could barely hear him say:
" . . . ooh . . . Sarah's . . . top . . . oorrgh"
exhaling his last breath and dying with the eyes wide open.