(Adds inspector general's spokesman comment, paragraph 7)
By Aruna Viswanatha
WASHINGTON, April 8 (Reuters) - A federal judge on Tuesday harshly criticized the U.S. State Department over its handling of a 2007 shooting in Baghdad involving Blackwater Worldwide security guards and asked the agency's watchdog to investigate problems that helped delay a related criminal case.
The prosecution of the former guards, who were charged with manslaughter in the killing of 14 unarmed civilians, has dragged on for years amid problems with evidence.
"If the Department of State and Diplomatic Security Service had tried deliberately to sabotage this prosecution, they could hardly have done a better job," U.S. District Judge Royce Lamberth, who is overseeing the criminal case against the former guards, said in an opinion dated March 26 but made public on Tuesday.
He asked the U.S. Attorney's Office in Washington, which is prosecuting the case, to ask the inspector general of the State Department to fully investigate the problems.
The issues stem from statements the guards were originally forced to give to State Department agents, which later made their prosecution more difficult.
A spokesman for the U.S. Attorney's Office declined comment. A representative for the State Department had no immediate comment.
A spokesman for the State Department's inspector general said U.S. Attorney Ron Machen referred the case to the agency's office on Monday and "we are carefully considering it."
The request comes as the former guards are expected to fight the charges at a June trial, seven years after the shooting occurred.
The shooting outraged Iraqis and strained ties between the United States and Iraq. Blackwater is now named Academi and is based in McLean, Virginia.
A grand jury indicted five Blackwater guards on manslaughter charges in 2008 over the shooting, which occurred as the guards escorted U.S. diplomats through the Iraqi capital.
The charges were thrown out in 2009 because of a dispute over whether evidence was tainted by statements the guards gave to Diplomatic Security Service agents under threat of losing their jobs.
Criminal authorities are unable to use such coerced statements in order to prosecute defendants, and must also prove their case was in no way tainted by those statements.
The case was reinstated in 2011, and prosecutors brought new charges against four of the guards last October.
"It is incredible the way these defendants were coerced into making statements to DSS agents," Lamberth wrote. "Yet it appears there has been no investigation of these circumstances and no one has been held accountable. Nor is there any reason to think anyone learned a lesson from this fiasco or that any steps have been taken to avoid a repetition," he said.
On Monday, the federal appeals court in Washington rejected the case against one of the guards. Jury selection in the case against the others is scheduled to begin on June 11. (Reporting by Aruna Viswanatha; Editing by Lisa Shumaker and Peter Cooney)