FORT LAUDERDALE (CBSMiami) – Jury selection in the death penalty trial of Parkland school shooter Nikolas Cruz is expected to resume on Monday following a week-long delay.

The delay was issued after both prosecutors and defense attorneys told Broward Circuit Judge Elizabeth Scherer they need more time to prepare for expert witnesses.

READ MORE: Redistricting Wrangling Goes To Florida Supreme Court

Judge Scherer has also already moved the start of the sentencing trial from May 31 to June 13.

Hundreds of potential jurors will be screened over the next few weeks as the pool is pared down to 12 plus eight alternates for a four-month trial.

To be selected, candidates must say they can judge Cruz fairly and vote for the death penalty if the evidence requires it. Under Florida law, all 12 jurors have to unanimously agree before the defendant is sentenced to death.

The jury will weigh whether the prosecution’s aggravating factors such as the multiple deaths, Cruz’s planning and his cruelty outweigh mitigating factors such as his lifelong mental health problems, possible fetal alcohol syndrome and the early deaths of his adoptive parents.

READ MORE: NOAA: 'Above Average' 2022 Atlantic Hurricane Season, Predicts 6-10 Hurricanes

The scale of Cruz’s killings, the extensive local media coverage and the trial’s length are requiring an extra-large pool of prospective jurors. The case is the deadliest U.S. mass shooting to make it to trial.

More than 1,200 potential jurors have been screened since April 4, with about 250 passing the first hurdle: Can they serve from June through September? Another 700 or more are likely to be screened starting April 25.

Cruz confessed to killing 17 people when he opened fire at Marjory Stoneman Douglas High School in Parkland on February 14th, 2018.

He pleaded guilty to the murders last October.

MORE NEWS: Insurance Bills Clear Committee, Move To Florida Senate Team