CHICAGO (CBS) — It could be an emotional day in court as the sentencing trial for former U of I student Brendt Christensen heats up.

CBS 2’s Audrina Bigos reports on who could be taking the stand.

We could hear from Yingying Zhang’s mother who’s expected to testify Tuesday, with the help of a translator.

On day one we heard from federal prosecutors who described the murder of Zhang as cold, calculated, cruel and months in the making.

Jurors must now decide if convicted killer Brendt Christensen should receive the death penalty or a life sentence without the possibility of release.

That’s what defense attorneys want. They’ll point to Christensen’s mental health struggles and that he sought help prior to Zhang’s murder  – to argue for life in prison without parole.

On the other side, prosecutors told the jury the crime deserves “extraordinary punishment.”

Last month, the same jury convicted Christensen of picking the Chinese scholar up in his car, then taking her to his apartment and choking, beating, stabbing and ultimately decapitating her.

Zhang’s body has not been found.

Chrsitensen’s interrogation by the FBI after Zhang disappeared is being used.

It’s possible Christensen himself could testify, with one theory being he might choose to reveal what he did with Zhang’s body as a way to save his life.