NEW YORK (CBSNewYork) — Closing arguments took place Monday in the trial of a Manhattan nanny accused of killing two young children in her care.

Web Extra: Prosecutors Make Closing Argument

Yoselyn Ortega is accused in the fatal stabbings of 6-year-old Lulu Krim and 2-year-old Leo inside their family’s Upper West Side apartment back in 2012.

Web Extra: Ortega’s Defense Makes Closing Argument

Ortega’s attorneys claim she’s not responsible due to mental illness, while prosecutors allege the murders were planned.

She faces life in prison in convicted.

With a look of disgust on his face, Kevin Krim sat in the courtroom, just a few yards from Ortega, the woman he once trusted to care for his children, CBS2’s Hazel Sanchez reported.

“Every stab, every slash, each one had a purpose. And that purpose was to end the lives of those children,” said Assistant District Attorney Stuart Silberg.

In their closing argument, prosecutors say Ortega had a well thought out plan to kill the children in 2012, and knew the consequences of her actions.

Ortega hardly reacted in court Monday, Sanchez reported. Her attorney says the 55-year-old suffers from severe psychosis and depression and heard voices telling her to kill the kids.

“The reason for the defendant’s actions lay within her delusional mind. The lack of the defendant’s apparent motive is the hallmark of her mental illness,” said defense attorney Valerie Van Leer-Greenberg.

But a video shown during the trial contradicts the defense claim, as Ortega is heard saying she never hear or saw Satan, Sanchez reported.

“Do you remember at all talking to [the devil] and you felt you being possessed by the devil, that the devil was taking control of your body?” asked psychologist Ali Khadvi. Ortega responded “no.”

Prosecutors claim Ortega acted out of anger against the Krims, particularly the children’s mother Marina Krim, for allegedly overworking her.

Marina Krim was not in court Monday.

The jurors will begin deliberating Tuesday.

The trial is in its sixth week. It was originally expected to last 3-4 months.