Nikolas Cruz, 19, is accused of killing 17 at Marjory Stoneman Douglas High School on February 14.
Peterson, an armed school resource deputy at the time and a veteran of the force of 33 years, was employed by the Broward County Sheriff's Department.
After spending 10 days in jail on a $500,000 bond, Cruz was eventually sentenced to six months of probation.
Zachary Cruz, the half-brother of Parkland high school gunman Nikolas Cruz, has been arrested again for getting too close to a Florida high school.
According to the Sun-Sentinel, Cruz was accused of violating his probation for driving on April 28 without a valid driver's license and for being within 25 feet of the parking lot at Park Vista Community High School in Lake Worth.
He was charged with trespassing, to which he later pleaded no contest.
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Zachary Cruz was booked Tuesday night into Palm Beach County Jail, according to the jail website. Among the conditions of his probation, he was ordered to stay away from Marjory Stoneman Douglas High school and any school where he wasn't enrolled. The brothers are both former Stoneman Douglas students.
A federal lawsuit was filed on Wednesday against Broward County officials for the "torture and violation of Zachary Cruz's Constitutional rights".
"We adamantly deny these new allegations and look forward to defending our position in court", said Cruz's attorney, Mark S. Lowry, on Wednesday.
"We all drive past and walk past schools every day and many public parks are located near schools so I'm concerned if, as it appears, BSO has violated him simply for going near a school".
His older brother, Nikolas Cruz, 19, faces numerous charges, including murder, for the shooting.
Civil lawyers for Zachary Cruz accused the Broward Sheriff's Office, prosecutors and the courts of "torturing" the teen and violating his civil rights "and engaging in an extortive campaign of intimidation because of the identity of his brother", according to a press release.