Peter Joseph Kovacs was the former husband of Sylvia Kovacs. Peter, however, is not the biological father of Walter Kovacs (aka Rorschach), as he and Sylvia were divorced some time before Walter's conception.
Very little is known about Peter. He married Sylvia Kovacs in the 1920s or '30s. Their marriage became strained in the late '30s, and each of them accused the other of psychological abuse and adulterous affairs. The two divorced, and presumably never met again. Following this, Sylvia became destitute and was forced to prostitute herself in order to survive and feed her child, Walter.