Amazing set of photos of NYPD 1978-81 by Jill Freeman here:

http://www.higherpictures.com/Exhibition.aspx?c=44

Super Cops comic from 1974. Apparently only one issue was ever printed by Red Circle, then also responsible for Archie. A single story from the comic, "2 to Get Ready and 4 to Go," is reprinted here:

http://drmonkeyretroblog.blogspot.com/2010/12/have-super-cop-christmas.html

Joseph Wambaugh's THE BLUE KNIGHT (1975)

Joseph Wambaugh's POLICE STORY

According to Herbert Packer in an article for New Republic (January 10, 1970, 12-13), "Gideon 1963": "made it essential for the states to afford the effective assistance of ounsel to criminal defendants." It should also be notes that Miranda v. Arizona established the basis of Miranda rights (a frequent cop film/ cop show trope). In essence, what Packer calls the "procedrual revolution" in law occurs in the 1960s, ensuring more and better rights for alleged criminals. This occurs though, in the supreme court. The legislative response, and still the law enforcement institutions themselves are much slower to change in accordance with these decisions.

The best source on the the cultural understandings of cops in America is in the work of Christopher P. Wilson, particularly his book Cop Knowledge and an article on Serpico and Prince of the City called "Undercover: White Ethnicity and Police Expose in the 1970s."