From Wikipedia:

As attorney general, ..[he] believed that the government's need for "law and order" justified restrictions on civil liberties. He advocated the use of wiretaps in national security cases without obtaining a court order and the right of police to employ the preventive detention of criminal suspects. He brought conspiracy charges against critics of the ... War, and demonstrated a reluctance to involve the Justice Department in civil rights issues. "The Department of Justice is a law enforcement agency," he told reporters. "It is not the place to carry on a program aimed at curing the ills of society."

Who is it? Here’s another quote:

the first United States Attorney General ever to be convicted of illegal activities and imprisoned.

No, we are not talking about the current U.S. Attorney General, Alberto R. Gonzales. John Mitchell has earned his place in history as the first U.S. Attorney General to be convicted of illegal activities. People have commented about how wily Gonzales is. He may be smart enough to avoid committing conspiracy, obstruction of justice and perjury as he tries to wiggle his way out of the investigations into the Justice Department that appear to be coming, Or, he might be a little bit too smart for his own britches and find himself earning his own place in history.

The Gavel Blog has House Judiciary Committee Chairman John Conyers, Jr. (D-MI) letter to U.S. Attorney General Alberto R. Gonzales