The homeless old man Kara sees in the streets as she drives with Todd to the house (credit scene, first Kara chapter), is the same we found dead (throat cut) on the chapter with Ralph (if we decide to stay with him) at the 2nd floor bathroom.

Given that when Kara sees the old guy alive from Todd cars he has a sign that claims: - “I lost my job because of ANDROIDS, help me!!” - we can assume that this person is not friendly to androids from the start, what might have transpired between him and Ralph is only speculation, but being homeless, surely tried to find refuge in the same abandoned house Ralph was (therefore Ralph mention that sometimes humans go to the house) , and the guy found Ralph, who, mentally unstable as he is, possibly stabbed him to death (there goes Ralph saying that “sometimes he does things that regret”) .

This is official canon for DBH.

Enjoy.