Good evening :)
Since you didn't include what kind of assistance you are seeking, I have just made some general comments.
First, make sure you are using linking verbs correctly so that your sentences are structurally sound. For instance, "I believe capital punishment is a
heavy punishment..." Also, make sure you are placing proper spaces between punctuation and words. For instance, "...(massacre),when there..." should be "...(massacre), when there..."
Make sure that your subjects and verbs all agree; when you are speaking about a singular object make sure that it does a singular verb. For instance, "...his reactions has roots..." should be "...his reactions have roots..."
Avoid using contractions in formal academic writing; always write out the full forms of the words you are contracting.
Make sure you aren't using run-on sentences, such as the last sentence of the piece. Try reading the sentence out loud to see where you naturally stop or get winded; that is where a period should be.
You could benefit from a grammar refresher, which would help with much of this essay. There are many guides online, or if you can get a hold of a copy, The Little, Brown Compact Handbook by Jane E. Aaron would be a great tool for you that I think would help you out immensely. You might be able to check it out from a library, or you can find it for sale on Amazon.
This is a great book that covers everything from spelling and mechanics to clarity and style; any questions you have I'll guarantee you can find in this book. Another good one is The Prentice Hall Guide for College Writers by Stephen Reid. It's much cheaper but you could also probably find this one at the library.
Best of luck!