What caused the massive spike in US crime rate in the 1960s?

by Cranyx

Since about 1990, the crime rate has been steadily dropping, but part of that is that we're "returning" to the rates that existed before 1960 when they skyrocketed, seen here Is there any consensus on what caused such an increase?

I'm aware that this question has been asked before

http://www.reddit.com/r/AskHistorians/comments/2i6xed/there_are_several_theories_why_the_us_crime_rate/

But the responses are almost all deleted except for one person who answered a piggybacked question.

Searocksandtrees

hi! not discouraging other responses here, but fyi, there was another related post that got a better discussion

Incidentally, there are a pile of interesting posts on urban decline if you're interested in more on that topic