U.S. District Judge Richard Matsch rules his courtroom with a firm gavel and a short temper. On Wednesday, he proved that observers cannot easily predict how he will rule on an important case.

Matsch's ruling in the Timothy McVeigh appeal surprised court-watchers who thought he would grant the Oklahoma City bomber a stay of execution.

Before issuing his ruling, Matsch said he found it "shocking" that thousands of FBI documents were withheld from McVeigh's lawyers until just last month.

"It's a good thing I was in quiet chambers and not in court," Matsch said of the moment he learned of the missing documents, "because my judicial temperament escaped me when I read it. It was shocking."

Observers thought Matsch was signalling that he would grant McVeigh a stay of his June 11 execution. But soon after, Matsch ruled that the execution would proceed as scheduled.

"Timothy McVeigh was the instrument of death and destruction," Matsch said. "Whatever role others may have played, it is clear Timothy McVeigh committed murder and mayhem as charged."

Matsch, the chief judge of the federal court in Denver, was assigned to the trials of McVeigh and Terry Nichols in 1996. The trials were moved to Denver because it was decided that passions were running too high in Oklahoma City for the two to get a fair trial there.

Matsch was credited with restoring confidence in the legal system. He imposed a gag order to prevent attorneys from trying their case on the courthouse steps, ruled decisively on matters of evidence and tolerated none of the antics seen at the O.J. Simpson trial in Los Angeles.

McVeigh, 33, was convicted of murder and other charges and sentenced to die for the April 19, 1995, bombing of the Alfred P. Murrah Federal Building, which killed 168 and injured hundreds of others. Nichols, 46, was convicted of involuntary manslaughter and conspiracy and sentenced to life in prison.

Through it all, Matsch refused to discuss the trials.