OAKLAND, Calif. -- Bay Area Rapid Transit General Manager Dorothy Dugger said Friday that she's asked the agency's detectives to complete their preliminary investigation into the shooting death of Oscar Grant III at the Fruitvale station in Oakland next week.

However, Alameda County District Attorney Tom Orloff said he's maintaining his timeline of taking two more weeks before he makes a decision on whether to file criminal charges against BART police officer Johannes Mehserle for shooting and killing Grant, a 22-year-old Hayward man.

The incident happened shortly after 2 a.m. on Jan. 1 when Mehserle and other officers stopped a train at the Fruitvale station in Oakland after receiving reports that two groups of men were fighting on the train.

Dugger said a team of nine BART detectives is working on the case and has interviewed all of the police officers who were on the platform at the Fruitvale station during the incident except for Mehserle.

Mehserle resigned on Wednesday so that he wouldn't have to talk to BART officials about the incident and he also has refused to talk to the district attorney's office, according to Orloff.

Mehserle's attorney, Christopher Miller of Sacramento, did not return a phone call for comment Friday.

BART, the district attorney's office and the Oakland Police Department are all investigating the incident, which has provoked outrage among the community because videos indicate that Grant wasn't armed, was lying on his stomach and was shot in the back.

Alice Huffman, the president of the California branch of the National Association for the Advancement of Colored People, is asking California Attorney General Jerry Brown to intervene in the investigation, saying in a statement that "citizens have little faith that local law enforcement personnel will seek justice."

Huffman and Brown spoke briefly by phone Friday and will meet in person on Saturday at Brown's office in Oakland. They will hold a news conference after they talk in private.

Dugger said BART directors will hold a meeting on Monday to create a new board committee that will examine BART police procedures.

Referring to Grant's shooting death, she said, "We want to make sure that such a terrible tragedy never occurs again."

Dugger said that at a five-hour public hearing at Thursday's BART board meeting, "We saw an extraordinary outpouring in which community members made their voices heard" about their unhappiness about how the transit agency has responded to the incident.

She said, "We heard their voices, their anger and their frustration."

Dugger said, "Yesterday's meeting was just the beginning of a dialogue with the community" and BART officials will hold a community forum on the incident at some point in the near future.

The Alameda County coroner's bureau said Friday that a preliminary report by a pathologist has determined that Grant's death was caused by a gunshot wound to his torso.

But the coroner's bureau said the pathologist's autopsy protocol won't be finalized for another eight weeks, as it will take that long for toxicology tests on Grant to be completed.