Denise Gay lived two doors down from the shooting, wherein rumored gang member Leroy Webster, following an earlier dispute, fatally shot Esui Johnson, and then opened fire when ordered to stop by responding officers. (Two officers were shot, as was Webster, who is currently in serious condition.)
Ballistic reports now indicate that the bullet recovered from Gay didn't come from Webster's gun, but rather that the bullet, "from a 9-millimeter gun, had markings consistent with those made by seven manufacturers’ guns, including Glock," the Glock 19 being one of the NYPD's three options for standard-issue service weapons.
Asked by reporters if the bystander may have been killed by an NYPD officer, spokesman Paul J. Browne responded, rhetorically, "'Was it one of the officers’ Glocks? Possibly.'" He added, "Was it from the gun witnesses said Mr. Johnson had, but has not been recovered? Possibly." Two witnesses told the NYPD that Johnson had a gun, but no such weapon was recovered at the scene. (They won't be able to match the fatal slug to a specific weapon as it was "deformed.")
It is possible that Johnson did have a gun; that it was a Glock or another of the 9mm semiautomatics whose bullet markings are consistent with the slug; that he fired it; and that it hit the innocent bystander. (The Daily News, who seem to be on this story the hardest of the three dailies—witness this impassioned play-by-play of some of the unreleased security-camera footage—report that of "several witnesses... [n]one recalled seeing Johnson with a gun.")
"Eight officers returned fire," on Webster after he turned and shot at them, the Times recounts, "in two two distinct volleys — firing 73 bullets and striking Mr. Webster twice, in his chest and hip. Two of those officers used Glocks to fire 15 rounds, the police said."
Asked by the Post if she thought a police bullet killed her mother, Tashmaya Gay replied, "'Look at the door,'" which the Post calls "bullet-riddled," which makes sense given that the 71 other bullets had to land somewhere.
With the obvious caveat that none of this would have happened if a guy with a long criminal record hadn't killed a guy and then tried to shoot his way out of an arrest, here is a quote, from an old-ish William Saletan piece on "contagious shooting," from one of the defense attorneys for the NYPD officers who shot the unarmed Amadou Diallo 19 times (out of 41 shots fired):
[NYPD rules] require that the officers carry nine millimeter semi-automatic pistols with 16 shots in the magazine and the first trigger pull being a conventional trigger pull and all subsequent trigger pulls being a hair trigger pull."
This was, of course, meant to reassure a jury that the Diallo shooting was neither horrifying nor malicious: it's just that the guns "'were all capable of being emptied in less than four seconds.'" (The use of the term "hair trigger" came under some dispute in the gun forums, but not the four seconds.) And hey, semi-fun fact: During the Dinkins years, Ray Kelly actually opposed the transition to semiautomatic service weapons.
In any case, though the integrity of the officers involved in the shooting is not and should not be called into question, their firepower probably ought to be.