OROVILLE, Calif. -

A man convicted of killing his mother in Chico in September of 2012 was sentenced to 26-years-to-life in prison Wednesday morning.

A jury found Adam Jacob guilty in the first degree for stabbing his mother, Donna Tiefer.

Police found Tiefer dead on her bed in her west Chico home on September 25th, 2012 with 43 stab wounds on her neck and face.

Investigators said during the attack, Jacob stabbed his mother's throat to stop her from screaming. The prosecution said Jacob’s motive was anger.

They say Jacob was angry that Tiefer was supporting his wife and child.

Tiefer's best friend and colleague Tina Brey was the only one who addressed the court Wednesday.

She shared the heartbreak that both she and Tiefer's families have been suffering in the last 18 months.

“How can he do that to his own mother? She gave him life and now he took hers,” said Brey during the sentencing.

Brey also said Tiefer would sometimes come to work with bruises on her arms and face.

The defense said Jacob should be eligible for probation.

The judge also ordered Jacob to pay more than $25,000 in restitution to the family. Jacob is ordered to attend drug and alcohol classes while he's in prison.