The storm surrounding embattled publishing icon Conrad Black gained momentum Thursday when four new U.S. federal criminal charges, including racketeering and obstruction of justice were leveled against him.

The former chief of Hollinger International Inc. was already facing obstruction charges from last spring, when he allegedly removed 13 boxes from Toronto offices while already under investigation.

Linda Sims, a business correspondent with CTV Newsnet, said the four new charges are some of the most serious so far against Black, and if proven, could land him in jail for a significant period of time.

"They're throwing the book at him, as they say in the movies," Sims said.

The charges, one each of racketeering, obstruction of justice, money laundering and wire fraud, were laid under the Racketeer Influenced and Corrupt Organizations Act (RICO), a tool created in 1970 to use against organized crime, which has lately been used against corporate crime.

RICO gives prosecutors the ability to seize assets related to the alleged crimes, which in Black's case could include his 68 per cent share of Hollinger International, worth millions.

"This is a blatant example of overreaching by the prosecutor," Black's Canadian lawyer Edward Greenspan said in a statement.

"No such initiative has been attempted in recent much larger white collar financial crime cases where there were allegations of accounting fraud, bankruptcy, thousands of people out of work, billions of dollars lost to investors -- none of which has occurred or is alleged here."

The new charges are more serious than the fraud charges already leveled against him, which are often reduced greatly during sentencing, according to Sims. Racketeering charges, if proven, carry a minimum of three years in jail, and 70 per cent of the allotted time must be served if the defendant is found guilty.

Thursday's new indictment in Chicago also adds new charges against Black's co-defendant John Boultbee, who is facing one additional count of wire fraud on top of the eight counts he was charged with Nov. 17.

Black has already been charged with eight counts of fraud. The U.S. Attorney's Office in Chicago alleges that the former head of Hollinger International took part in a scheme to divert more than $80 million US from the company.

Each count calls for a penalty of five years in prison, and Black has pleaded not guilty to all eight.

Judge Amy St. Eve has released Black on a $20 million US bond, allowing him to travel between Canada and the U.S.

He secured his bond using his Palm Beach, Fla. home and roughly $8.5 million US in assets from his New York apartment, which was seized by the Federal Bureau of Investigation.

Canadian-born Black, who currently resides in Toronto, famously gave up his Canadian citizenship to become Britain's Lord Black of Crossharbour after a dispute with former prime minister Jean Chretien. Recently, however, Black applied to have his citizenship reinstated.

Black has filed his own $110 million defamation suit against Hollinger International.