Attorneys for Nikolas Cruz on Monday will begin making their case that the man who killed 17 people and wounded 17 others in a 2018 mass shooting at a high school in Parkland, Florida, should not be given the death penalty.

Prosecutor Michael Satz told Broward County jurors in July that Cruz should be put to death for "goal-directed, planned, systematic murder -- mass murder -- of 14 students, an athletic director, a teacher and a coach."

Cruz, 23, pleaded guilty in October to committing premeditated murder at Marjory Stoneman Douglas High School in Parkland, about 30 miles (50 km) north of Fort Lauderdale.

His attorneys are expected to argue that Cruz should receive life without parole due to mitigating factors, including his brain damage from his mother's drug and alcohol abuse during pregnancy, his history of mental-health disorders, and allegations he was sexually abused and bullied.

Under Florida law, a jury must be unanimous in its decision to recommend that a judge sentence Cruz to be executed.

Cruz said in his guilty plea that he was "very sorry" and asked to be given a chance to help others.

The start of the penalty phase of the trial last month included testimony from students who were at school that day and cellphone videos in which terrified students cried for help or spoke in hushed whispers as they hid.

U.S. gun violence gained renewed attention following recent mass shootings, including one at a July Fourth holiday parade outside Chicago that killed seven people and another in May at a school in Uvalde, Texas, that left 19 children and two teachers dead.

President Joe Biden in June signed the first major federal gun reform in three decades, which he has celebrated as a rare bipartisan agreement.