Amelie Le Moullac, 24, was killed when a truck made a right turn at Sixth and Folsom streets and struck her on the morning of Aug. 14.
The truck driver was not initially cited, but police Chief Greg Suhr said Thursday that after an investigation by the Police Department's major accident investigation team, the driver was found to be at fault.
Suhr said the case is being presented today to the district attorney's office, which will make a decision about whether to charge the driver.
Suhr said a critical part of the investigation was surveillance video footage of the accident uncovered by members of the San Francisco Bicycle Coalition.
The coalition organized an event at Sixth and Folsom streets a week after the accident, and its members found the recording after talking to owners of nearby businesses. The video was then passed along to police and the attorney for Le Moullac's family.
The coalition has criticized the Police Department's handling of the case, both for not finding the surveillance video and for a sergeant who allegedly stopped at the event last week, parked in the bike lane and told people there that Le Moullac was at fault for the collision.
Suhr said Thursday that the department is apologizing for that incident.
"It's never OK for anybody, let alone a police officer, to be a distraction at a memorial," he said. "We're usually better than that."
He said video of the incident involving the sergeant has been forwarded to the city's Office of Citizen Complaints, which handles allegations of police misconduct.