Dick Cheney fears being charged as a war criminal, former Colin Powell aide says

The sniping between Dick Cheney and his erstwhile Bush administration colleagues ratcheted up Tuesday when a long-time aide to Colin Powell said the former vice president is afraid of being prosecuted as a war criminal.

Col. Lawrence Wilkerson, who served as chief of staff to Powell when he was secretary of state in the first term of President George W. Bush, said Cheney has changed into an unrecognizable figure since his time as secretary of defense under President George H.W. Bush.

"He's developed an angst and almost a protective cover, and now he fears being tried as a war criminal," Wilkerson told ABC News, "because that's the way someone who's decided he's not going to be prosecuted acts: boldly, let's get out in front of everybody, let's act like we are not concerned and so forth when in fact they are covering up their own fear that somebody will Pinochet him."

Former Chilean dictator Augusto Pinochet was arrested for war crimes years after relinquishing power.

Wilkerson, who has known Cheney for decades, said Cheney has become a "very vindictive person" and "I simply don't recognize Mr. Cheney anymore."

Wilkerson has been an outspoken critic of the Bush administration since he left the State Department in 2005. In addition to serving as Powell's chief of staff at the State Department, Wilkerson was a top aide to Powell when the Army general was chairman of the Joint Chiefs of Staff in the first Bush administration. At that time, Cheney was defense secretary.

Cheney is promoting a new memoir, "In My Time: A Personal and Political Memoir," and said ahead of Tuesday's release that heads would explode when the book came out.

Powell shot back, telling CBS' "Face the Nation" that the former vice president was taking "cheap shots."

"I think Dick overshot the runway," Powell told CBS News' Bob Schieffer, adding that his tease that the memoir will "makes heads explode" is a comment he would have expected from a gossip columnist, not a former U.S. vice president.