A Columbia man pleaded guilty to first-degree murder and armed robbery yesterday in the slaying of an armored-car guard, in exchange for a sentence of life plus 20 years.
Assistant state's attorney Timothy Wolf, who prosecuted the case, said Tyrone Colbert, 29, could have received life plus 40 years in the shooting death of Frederick John Cook Jr. of Middle River.
Mr. Cook, a guard for the Loomis Armored car company, was slain Jan. 11, 1990, outside the Signet Bank at Long Reach Village Center in Columbia.
Robert G. Landolt, Colbert's lawyer, said he was satisfied with the sentence.
Circuit Judge Raymond J. Kane Jr., who sentenced Colbert yesterday, ruled in December that he could not be given the death penalty or life without parole in the case because prosecutors had not told him in person of their plans to seek those penalties.
Colbert's co-defendants in the murder case, Stephen A. Brock of Laurel and Patricia Talkin Whitted of Silver Spring, pleaded guilty to armed robbery before Judge Kane in December.
Brock, the getaway driver, and Whitted, the lookout, were sentenced to five years in prison and five years of supervised probation.
Prosecutors said the co-defendants gave police a semiautomatic handgun believed to be the murder weapon. The two had agreed to testify against Colbert, who is now serving a three-year sentence for a 1989 holdup in Baltimore County.