Fitzgerald was fatally shot while responding to reports of a robbery near Temple's campus back in February.
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Shortly after the shooting, authorities arrested 18-year-old Miles Pfeffer from Bucks County.
READ | Suspect, 18, arrested in Bucks County for Temple University police officer killing
Pfeffer was charged with murder, murder of a law enforcement officer and related offenses, according to the Philadelphia district attorney's office.
He also faces charges in connection with a carjacking he allegedly committed after the killing.
A civil lawsuit was filed Thursday against Pfeffer's father, mother, and the mother's boyfriend for negligence and wrongful death.
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The lawsuit claims the family knew about Pfeffer's mental instability and interest in firearms before the incident.
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It also names Pfeffer for wrongful death, assault, and battery.
The 31-year-old fallen sergeant is survived by his wife, four children, and his parents.