Desperate to deliver the perpetrators of July’s Brownsville mass shooting to justice, police upped a reward to $20,000 Thursday for help tracking down a pair of women believed to know at least one of the shooters.

It’s been nearly 10 weeks since a pair of unknown gunmen opened fire during the Old Timer’s Day block party in Mendoza Park just before 11 p.m. on July 27 — leaving one dead and 11 others injured — and no arrests have been made.

“C’mon, NYC,” NYPD’s Chief of Detectives Dermot Shea wrote Thursday afternoon in one of two pleas for the public’s help in closing the case, sharing photos of two persons of interest in the mass shooting.

On Wednesday, the NYPD released a cellphone video from that night showing the two women, who are wanted for questioning about their connection to the shooters.

Police sources told The Post the murder weapon used during the summer block party was found in one of the unknown women’s backpacks, which was recovered by detectives at the scene. Sources said neither is believed to have pulled the trigger.

Two people are believed to have opened fire during the block party — despite some 100 cops patrolling during the event at Christopher and Hegeman avenues in Brooklyn.

Police sources previously said they believed a gang dispute set off the shooting, but the NYPD has not publicly released a reason for the bloodshed.

When asked about the case during a press conference last month, Police Commissioner James O’Neill wouldn’t go into detail on the investigation and said there’s a “tremendous amount of work being done on that case.”

Shea reminded folks Thursday the reward can be claimed anonymously, and ended his second tweet with the hashtag, #MeanGirlsDay — a reference to the 2003 flick “Mean Girls.”