A woman broke down and sobbed on the stand today during the second degree murder trial for a Calgary mother who is accused of killing her teenaged daughter.

Layla Magomadova took the stand on Tuesday at her sister's murder trial.

Aset Magomadova is accused of the second degree murder of her 14-year-old daughter Aminat back on February 26th of 2007.

Aset claims she killed Aminat in self defense in her home after her daughter attacked her with two knives.

When police arrived at the southwest home they found the strangled body of Aminat and police say Aset described to them how she'd used a scarf to kill her.

Even though Layla was a crown witness, she broke down under cross examination as she described what she heard and saw the morning Aminat died.

She said she heard Aset say "drop it, drop it" and she sobbed as she described the sewing room where Aminat was lying dead.

"Her evidence was obviously rending, she was broken up several times including one case in which the court had to stop because she was so upset," said Defence Attorney, Mark Tyndale.

Layla Magamadova also testified that she heard her sister say "ow" after apparently being cut with a knife but a crime scene officer testified last week that there was no blood found at the scene.