More than four years after taking the lives of 17 students and staff at Marjory Stoneman Douglas High School in Parkland, Florida, the man who pleaded guilty to the attack is likely facing life in prison and not the death penalty, much to the dismay of many Parkland parents whose children were killed in the shooting.

Tony Montalto, whose daughter Gina was one of the Parkland victims, said on Greater Boston he was shocked, angered and frustrated by the sentencing.

"As a society, we should want him punished to the fullest extent of the law in order to discourage others that would think about attacking our nation's future by going into a school, attacking our most vulnerable students and teachers. I think that we need as much deterrence for that as possible," Montalto said.

But James Rooney, president of Massachusetts Citizens Against the Death Penalty, said sentencing someone to death doesn't necessarily heal the victims.

"If you're looking at this in terms of the death penalty helping victims, I think it's a false hope. The idea that sentencing someone to death is going to help the victims heal, I don't think is true," Rooney said, adding that the majority of death penalty cases do not actually result in the death penalty.

Both guests noted the importance of limiting the use of the shooter's name in the media and other public settings, as it helps to take away notoriety that many seek.

"Sadly today, we still see people paying homage and remembering the Columbine shooters, so we have to start reducing the notoriety of these shooters," Montalto said.

"The person who gets remembered around the mass killings tends to be the shooter. The names of the victims go by the wayside," Rooney added.

Watch: ‘We should want him punished to the furthest extent of the law’: Parkland father on sentencing