The words "poor" and "needy" refer to the same group of people and emphasize that these are people who are unable to help themselves. (See: [[rc://en/ta/man/jit/figs-doublet]])
The murderer kills in secret just like a thief steals without anyone seeing what he does. Alternate translation: "he kills people secretly, just like a thief steals secretly" (See: [[rc://en/ta/man/jit/figs-simile]])