(NewsNation) — Marjory Stoneman Douglas High School shooter Nikolas Cruz, who admitted to killing 17 people in 2018, was sentenced to life in prison earlier this week, rather than receiving the death penalty for his crimes.

Families of those he killed were outraged at the sentencing.

“I was convinced this person was going to die, that this person was going to receive the death penalty, I was waiting to see if a state that has the death penalty would apply it in this case,” said Manny Oliver, whose son Joaquin was murdered by Cruz. “If not in this case, when do you use it?”

“The system failed Joaquin again,” Oliver added

A jury of 12 must vote unanimously to invoke the death penalty in Florida, but the jury in Cruz’s trial ultimately sided with the defense’s argument that Cruz was developmentally disabled because his birth mother drank heavily during pregnancy.

“I don’t think having mental health issues is an excuse to get away with the murder of 17 innocent people, there’s a lot of people with mental illness, not only in this country but all around the planet,” Oliver said. “They just cannot use that as an argument to convince a jury that this person (did) not deserve dying.”

Most upsetting to Oliver about Cruz’s sentence is that Cruz will get to continue living life after he took Joaquin’s forever.

“He will go to prison, make friends, watch TV. He will see the Super Bowl that my kid used to love, that he won’t watch anymore. He will watch Netflix and movies and he will learn how to live that way,” Oliver said. “It’s hard for me to learn how to live this way after losing my son.”

Oliver, like other parents who spoke after the sentencing, hope Cruz’s stay in prison is “hell.”

“I hope there is a lot of suffering,” Oliver said. “After I heard the autopsy of my son and the way he suffered and the painful way he, without deserving anything, being an innocent guy celebrating Valentine’s Day, died, he was shot four times and he suffered while he was dying. I don’t think anything that happens to this shooter in prison is going to be at that level of painful. But I really hope that he suffers, I really hope that it is hell for him.”