How to tell if you were hit with a Panda/Penguin Penalty and how to Recover?

I remember in 2012 at the tail end my site received a record high traffic for a single keyword in its niche. I had 5 articles up that day that were in Google news. I earned a couple hundred dollars on adsense i was stoked.

A few days later when I was publishing some articles on follow up first hand reported stories from my bloggers we no longer ranked high for that keyword, now we rank at page 300 for that single keyword.

Every time we post up a new article and do a title specific search the article will not appear on the first page, but on the top of page number 2 of google search.

Scrapers will also outrank us with our own content even though many of these scrapers are linking back to us as the original and only post a excerpt they are out ranking us and on the first page.

Our website is 7 years old and much older than the scraper sites, in fact 3 of the scraper sites are just forums and round 1 to 2 years old only.

So that Domain Authority aka AGE requirement or seniority that google claims is out the window that doesn't mean much.

I know many people say Negative SEO doesn't exist, but could it be possible a competitor in my niche who was mad that I was ranking higher than them reported my articles as spam with multiple dummy IP's and accounts? and that it could penalize us?

Like described here about reporting competitors who you feel are spamming google didn't realize thy could have opening up a way for negative SEO with this because there could be a lot of fake anonymous reports just to bring you down as spam

http://www.seroundtable.com/google-r...-us-15187.html

Also can a lot of 404 not found pages or pages you deleted from years ago trigger a algo penalty and lower your ranking?

Is this a sign of an Algorithmic penalty? How does one recover or is it impossible at this point and one must start from scratch with a new site with the penalties awareness in mind?

http://www.rainbodesign.com/seo-tips...nking-drop.php