MARTINEZ -- A Southern California couple pleaded not guilty Friday to murder and other felony charges in connection with the Oct. 5 killing of retired schoolteacher Susie Ko at her Hercules home.

Tania Washington, 25, quietly cried in her hands as defense attorneys entered the pleas for her and her 24-year-old husband, Darnell Washington.

Authorities say the West Covina residents fatally stabbed Ko, 55, during a crime spree that started with Tania Washington helping her husband break out of a San Bernardino County jail on Aug. 28 as he was awaiting trial on robbery charges.

It was while on the run for the jail break, authorities say, that Darnell Washington shot and wounded a Los Angeles County sheriff's deputy on Sept. 2.

Police in SeaTac, Wash., apprehended the couple Oct. 10 after they allegedly led officers on a high-speed chase in KO's stolen Subaru Outback and rammed a patrol car.

The nine-count felony complaint filed against the Washingtons in Contra Costa County Superior Court alleges that they murdered Ko in the course of a robbery, burglary and a carjacking -- special circumstances that make the couple candidates for a death penalty prosecution. The Contra Costa District Attorney's Office has not announced whether it will pursue capital punishment.

After the Contra Costa County case is resolved, the Washingtons are expected to return to Los Angeles County for prosecution on charges that include attempted murder of a peace officer, carjacking and attempted carjacking.

Court documents indicate that the Washingtons went to KO's house after ditching the stolen truck they used to flee a robbery at the Pinole Kmart, located just one freeway exit from the Ko family's neighborhood.

"There is an active investigation into other possible criminal activity that took place between the time Mr. Washington escaped in San Bernardino and their capture in Washington (state)," deputy district attorney Molly Manoukian said.

The Washingtons return to court March 1 to schedule a preliminary hearing. In the meantime, they are being jailed without bail.

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.