MOUNT VERNON — Jury selection will begin Monday in the trial of a Sedro-Woolley-area couple accused of abusing their adopted Ethiopian daughter to death in 2011.

Larry and Carri Williams are charged with homicide by abuse and first-degree manslaughter in Hana Williams’ death. Both have pleaded not guilty.

The homicide-by-abuse charge applies only if the victim was younger than 16, and Hana’s exact age has been at issue throughout the investigation. She is believed to have been 13 when she died, but documentation of her birth has been unavailable.

Witnesses for the defense could testify that birth certificates are issued in fewer than 15 percent of Ethiopian births, and that birth dates given for adopted children are often unreliable or inaccurate, according to court documents.

Motions Friday by Carri Williams’ attorneys to postpone the start of the trial were denied. Attorney Wes Richards said repeatedly that he and attorney Laura Riquelme were not prepared to provide adequate counsel for Carri Williams because they had received some evidence from the state as late as Friday.

Judge Susan K. Cook, who is presiding over the case, said a “last-minute flurry of activity” is typical.

Prosecutors and Larry Williams’ attorneys had both opposed that motion, with Larry Williams’ attorneys arguing he has spent 19 months in custody and should not have to wait longer for his day in court.

“This is a situation where one side holds all the cards,” said Larry Williams’ attorney, Rachel Forde, gesturing to the prosecution and then to her client, “and one side is facing all the jeopardy.”

Larry Williams, unlike his wife, has been held at the Snohomish County Jail under Skagit County’s custody.

The couple also are charged with first-degree child assault, tied to allegations they physically abused their Ethiopian adoptive son.

Hana was found lying dead in the mud in the backyard of the Williamses’ home on a rainy night in May 2011. She died of hypothermia hastened by malnutrition and a stomach condition, according to the autopsy report.

Investigative reports detail allegations that the Williamses starved Hana, beat her and forced her to live outside.

About 125 people will be called in Monday as possible jurors. That group eventually will be whittled to 15 — 12 jurors and three alternates, Cook said Friday.