Diallo’s mother, Kadiatou Diallo, said the NYPD decision to restore Officer Kenneth Boss’s service weapon was a betrayal, reports the New York Times.

Amadou Diallo, an unarmed immigrant, was gunned down by police officers who mistook his wallet for a gun. The notorious incident took place in the vestibule of his apartment building in the Bronx on Feb. 4, 1999.

According to the New York Post, Boss had battled three consecutive police commissioners for the right to carry a gun again.

The NYPD did not offer any explanation about the gun restoration.