A Howard County Circuit Court judge ruled yesterday that the state cannot seek the death penalty against a Columbia man accused of murder because prosecutors failed to directly notify the defendant of their plans to request that sentence.

Tyrone Michael Colbert, 28, is accused of being the trigger man in the robbery and killing of Frederick J. Cook Jr., 58, an armored car guard from Baltimore. Cook was shot to death at the Long Reach Village Center in Columbia in January as he delivered money to a Signet Bank. Colbert's trial, which was scheduled to begin yesterday, has been postponed until Jan. 28.

Judge Raymond J. Kane Jr. said that Maryland law specifically orders that the state notify the defendant personally after a decision to ask for the death penalty or life imprisonment without parole.

Prosecutors notified Colbert's lawyer, Robert Landolt, but not Colbert. Landolt asked Kane Thursday to strike the state's request for capital punishment or a life sentence without parole because he said only he had been notified.

"I'm pleased with it," Landolt said of the judge's ruling. "I think it was the appropriate ruling."

Prosecutor Richard O'Connor said that in previous cases, he has notified either defense counsel or the defendant. "I've never been challenged on this issue before," he said.

Anna Cook, Frederick Cook's widow, was angered by Kane's decision. "I don't like it," she said. "I don't like it at all. I feel like I've been a victim twice. I just hope he's able to sleep tonight."

Two codefendants in the case, Stephen A. Brock, 23, and Patricia T. Whitted, 32, pleaded guilty yesterday to armed robbery.

Brock, of Laurel, and Whitted, of Silver Spring, both accused of assisting Colbert in the slaying, were to be tried on charges of murder, armed robbery and weapons violations. They were sentenced by Kane to five years in prison with five years of supervised probation after serving their time.

As part of the plea bargain, all other charges against Brock and Whitted were nullified, and both have agreed to testify against Colbert.

Yesterday's ruling came after a closed-door pretrial hearing held by Kane last Thursday, after which he issued a gag order prohibiting those present from discussing the hearing publicly.

Sources said that the hearing concerned plea negotiations that had taken place between the state and defense lawyers. The state had to withdraw from the plea agreement after Anna Cook strenuously objected to it, sources said.

Both O'Connor and Landolt declined to say yesterday whether Kane's ruling would cause plea negotiations to begin again.