The Alameda County District Attorney’s handling of the Oscar Grant murder continues to disappoint anyone hoping that justice will prevail.

The most recent reason to doubt District Attorney Tom Orloff’s commitment to convicting Grant’s killer came late last month, when local TV news began echoing what most people who’d watched videos of Grant’s murder already knew: it wasn’t just one cop attacking Grant on that subway platform.

Before Grant was killed, Officer Tony Pirone punched him in the face without cause, hitting him so hard that Grant dropped to the ground. Legal scholars called it criminal. But the District Attorney had already said that he wasn’t pursuing charges against other officers, and that story didn’t change even after the damning evidence of Pirone’s role was widely broadcast.

It took two weeks and thousands of people speaking out before the DA charged Johannes Mehserle, Grant’s killer, with murder. Clearly, it will take continued public pressure to see that justice is served throughout this case. On Tuesday, those of us in the Bay Area will publicly confront District Attorney Tom Orloff with over 20,000 petitions demanding that Orloff explain his refusal to charge Pirone. It’s also time to put pressure on California’s Attorney General to keep an eye on how Orloff handles the case. The state-level observer Brown placed in Orloff’s office was inexplicably removed as soon as Mehserle was arrested.

Local news reported on the video that shows Pirone assaulting Oscar Grant late last month, but it has been on the Internet for weeks. As with the shooting, the video doesn’t leave a lot of room for explaining away Pirone’s actions. It makes it clear that with no physical provocation, he punched Oscar Grant so hard that Grant immediately went down. This is assault, and it is a crime.

Law professor Peter Keane from UC Hastings College of the Law, couldn’t have said it any clearer than when he appeared on local TV news: "If the district attorney is saying he’s not going to charge any officer except Mehserle, in my opinion he’s not doing his job."

Keane told ColorOfChange that Pirone’s lawyer’s claim — that Pirone struck Grant with his forearm in accordance with police procedure — doesn’t jibe with what he saw in the video.

"What I saw was a fist, a real roundhouse right punch and the fist land," Keane said. He went on to dispute the notion that Orloff might be holding off on charging Pirone–who had his knee on Grant’s neck when Mehserle shot the 22-year-old–in exchange for Pirone’s cooperation against Mehserle. Keane noted that Pirone’s story seeks to buoy Mehserle’s claim that he meant to use his Taser, not his gun, on Grant.

"It appears that both Mehserle and Pirone’s interests are to enforce each others’ stories," Keane told ColorOfChange. "I think their interests now are in lock step together."

The District Attorney’s inaction further calls into question his commitment to justice for Oscar Grant. Given Alameda County’s terrible record of prosecuting police abuses, we cannot simply trust that Orloff’s office has the will to pursue justice wherever it leads.

California Attorney General Jerry Brown should return an observer to the Alameda County District Attorney’s office for the duration of any prosecutions related to Oscar Grant’s murder. And Orloff needs to tell the public how not seeking charges against Pirone could possibly be in the interest of justice.