LOS ANGELES >> It took seconds for a freight train to kill Sarah Jones, a 27-year-old camera assistant who died on the set of an independent film, "Midnight Rider," in rural Georgia on Feb. 20.

Sorting through the consequences may take years.

As Hollywood weathers the initial shock of a rare fatal accident during a film production — a candlelight walk along Sunset Boulevard was the most visible of several memorial events here and elsewhere — a complicated tangle of county, federal and private investigators is sorting through narrow questions of specific responsibility.

These questions may also address a broader issue: Can, or should, independent movie productions, ranging from no-budget student films to star vehicles underwritten by state subsidies, be more closely policed for on-set safety?

"There was clearly a disregard for some very important protocols," said Ray Brown, president of the International Alliance of Theatrical Stage Employees Local 479 in Atlanta. "Who disregarded them, the investigations will tell."

Brown said he was inclined at this point to see Jones’ death as "an isolated, very unfortunate incident" without wider implications. He said film shoots in Georgia, which has subsidized a growing number of productions in recent years, generally adhere to strict safety procedures that would have prevented the accident if they had been observed.

But others say film crews are being pushed too far. "As a result of apparent negligence and an entire disregard for safety and common sense, our daughter is now dead," Jones’ parents, Richard and Elizabeth Jones, said in an email statement, underscoring a point that was made by Jones’ industry colleagues at the various memorials.

"From her unnecessary death," the Joneses said, "a cry for safer film sets has circled the globe."

Ultimately, debate about the possible need for more oversight will turn on the answers to basic questions about what went wrong — and those remain far from resolution.

Jones was killed while helping to prepare a shot that involved placing a bed across the tracks of a CSX railroad line near Doctortown, Ga., about 60 miles southwest of Savannah. After two trains passed, crew members on the film, a biopic about the rock musician Gregg Allman directed by Randall Miller, believed they would have a safe interval to get the shot, for a dream sequence. But a third train appeared, moving at high speed through the set, killing Jones, injuring others, and nearly adding Miller to the victims.

The question of whether producers were on the tracks without permission from CSX is under examination, according to people connected with one of the various inquiries, who spoke on condition of anonymity because the investigations are incomplete. The inquiries, these people said, are also examining whether the railroad should have slowed or stopped the third train after the first two passed the gathered film crew — if it can be shown that railroad employees should have seen a potential for trouble.

The Occupational Safety and Health Administration and the National Transportation Safety Board are investigating the incident.

Terry Williams, a spokesman for the NTSB, says his agency typically takes as long as a year to complete an investigation and develop recommendations about any proposed changes in transportation-related procedures. Jesse Lawder, an OSHA representative, says that agency only has the authority to issue citations within six months of a workplace safety violation.

Gary Sease, a spokesman for CSX, said the railroad was cooperating with investigators, but declined to comment further.

In a separate inquiry, the sheriff’s department in Wayne County, Ga., where the accident occurred, is in the middle of an investigation that could conceivably lead to criminal charges, though none had been recommended to prosecutors as of last week.

Matthew Hiltzik, a spokesman for the "Midnight Rider" production, declined to discuss the inquiries, or answer questions about how the film was financed or whether it would be completed; work on the film was suspended after Jones’ death.

The movie, in which William Hurt portrays Allman, was set for distribution in the United States by Open Road Films, but at the time of the accident it did not yet have a release date. A spokeswoman for Open Road declined to discuss the film’s future.

The director, Miller, who is also a producer of "Midnight Rider," is now represented by Harry D. Dixon Jr., a lawyer based in Savannah who was the U.S. attorney for the Southern District of Georgia under the Clinton administration. The presence of Dixon, known widely as Donnie, points to the high stakes in the various inquiries into the accident.

In the last week, those inquiries have included a private investigation by Jeffrey R. Harris of Harris Penn Lowry, a Savannah law firm that was recently retained by the Jones family. Harris is expected in the next few weeks to file one or more civil complaints in connection with the accident.

Reached Thursday, Harris declined to discuss his legal strategy, but he made clear that questions about conduct in the film industry, particularly among smaller independent operations, were not off the table.

"There’s a lot of pressure on these producers and directors to make these films under budget," Harris said. "It would have cost them a lot more to have the railroad shut down."

Jones’ death has recalled another on-set disaster, a helicopter crash in 1982 that killed the actor Victor Morrow and two child actors, Myca Dinh Le and Renee Shin-Yi Chen, on the set of "Twilight Zone: The Movie," a Warner Bros. film.

After the crash, John Landis, the director of the anthology film’s prologue and the segment affected by the accident, and four co-workers were tried for manslaughter. They were acquitted, but the trial shook the film industry, and might have curtailed the authority of swashbuckling directors, who found themselves more closely watched by safety monitors.

"You became more aware of it after that," said C.O. Erickson, a veteran line producer who spoke last week of the enhanced consciousness of safety that pervaded studio-level filmmaking after that accident.

The biggest Hollywood films, Erickson pointed out, are overseen by studio safety officers who check and crosscheck potentially hazardous situations, making an accident of the kind that killed Jones almost unthinkable. But smaller productions, Erickson said, rely heavily on the professional skills of production managers and, especially, assistant directors, who check details that might escape a harried director.

A frequent safety complaint among film crews working on both studio and independent productions centers on a common practice of demanding long workdays of 14 or more hours. The filmmaker Haskell Wexler described the hazards of long days in his 2006 documentary "Who Needs Sleep?" Among other things, he recounted how lack of sleep led to the driving death of an assistant camera operator in 1997.

Still, a vast expansion of movie and television production in states that use tax incentives to support both independent and studio films does not appear to have resulted in a rash of serious accidents like the one on "Midnight Rider."

In Georgia, where film permits are overseen by local municipalities, state money helped to subsidize more than 140 movie and television projects in the last year, without a similar mishap, according to state officials.

For many, however, Jones has become a symbol of the need for safer sets.

A bit of street art spotted on Wilshire Boulevard here last week pointed to her new status as a kind of guardian angel for film crews. It was a yellow and black placard, in the familiar style of road signs that point toward movie locations.

The only words were "Sarah Jones." The directions — a set of hearts and arrows — pointed straight up.