Two brothers charged with the murder of a Philadelphia police officer were formally arraigned Thursday on charges related to a series of armed robberies in the months leading up to the fatal shooting of Sgt. Robert Wilson.

Carlton Hipps, 30, and Ramone Williams, 26, are both in custody charged with the murder of Wilson, an eight-year veteran of the force who left behind two grieving young sons. They allegedly killed Wilson a little over a year ago during a botched attempted robbery of a Gamestop at 22nd Street and Lehigh Avenue that resulted in a furious gun battle with police.

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Hipps and Williams were arraigned on charges related to the armed robberies on Nov. 15, 19 and 26; Dec. 9, 17 and 18 in 2014; and Feb. 19, 2015, according to court documents.

All the robberies occurred in the 22nd District, where Wilson was assigned, the Inquirer reported.

The brothers allegedly entered the Gamestop while Wilson was inside doing a routine security check and to buy a game for his son's birthday on March 5, 2015, just after 5 p.m.

After realizing a police officer was inside the store, the two opened fire, fatally wounding Wilson, according to police and prosecutors.

Hipps was apprehended after he tried to flee and was shot outside by Wilson's partner. Williams was arrested hiding in the store, despite claiming to police that he was a customer.

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A spokeswoman for the Philly DA's office declined to comment on the new charges.

Hipps and Williams are scheduled to face a judge for preliminary hearings on the robbery charges on June 23 and 24.