Tony Stewart is not currently facing criminal charges over the on-track incident during a sprint car race that resulted in the death of fellow racer Kevin Ward Jr.
Ontario County Sheriff Phillip C Provero told a media conference on Sunday that an initial examination of available evidence does not support the accident being considered a criminal matter.
"At this moment there are no facts or evidence that would support a criminal charge or criminal intent," he said.
"This is, right now, being investigated as an on-track crash, and I don't want to infer that there are criminal charges pending.
"When the investigation is completed we will sit down with the District Attorney and review it, but I want to make it very clear that there are no criminal charges pending at this time."
Stewart has been cooperating with authorities in the investigation and was described by Provero as "visibly shaken" by what had happened on Saturday night.
The incident began when Ward and Stewart made contact during a race at Canandaigua Motorsports Park, an hour from Watkins Glen, where the NASCAR Sprint Cup was racing last weekend.
Ward spun out, climbed from his car, and walked down the track gesturing at Stewart as the three-time Cup champion looped back around.
Stewart's car fishtailed as it passed the 20-year-old, hitting him with its right-rear wheel and flinging him to the side of the track. He was pronounced dead at nearby FF Thompson Hospital.
A statement from Ward's family read: "We appreciate the prayers and support we are receiving from the community, but we need time to grieve and wrap our heads around all of this."
Regan Smith stood in for Stewart in Sunday's Cup race at Watkins Glen; the veteran finishing nine laps down in 37th after a late incident.