How did Shimada Die? He was shown killing Tatsumi, the detective, then the flashback was over.

 

Nowhere in the anime did it show how he died (and came for judgement). How did he die?

Canonical answers would be appreciated!
On the reddit thread discussing the episode, the same question popped up, to which there was this reply:


  He got stabbed by the guy who assaulted his sister. We saw the latter grab a knife from the kitchen sink and stab him in the hip/back. You can also see blood staining Shimada's shirt from under his knapsack after he stabs Tatsumi. Actually, he probably could have survived if he didn't overwork himself killing the detective.


Pictures replicated here in order mentioned:


   
 


So basically, he got stabbed but passed out after killing the detective, then bled to death from his earlier injuries.