Tony Stewart, a three-time NASCAR Sprint Cup Series champion, has pulled out of a scheduled start in a dirt-track race Saturday at Plymouth Speedway in Indiana, track officials confirmed.

Stewart, 43, sat out Sunday’s Sprint Cup Series race in Watkins Glen, N.Y., after his involvement in the death of fellow racer Kevin Ward Jr. at an upstate New York dirt track on Saturday night.

A sprint car driven by Stewart struck and killed Ward as the 20-year-old was walking on the track, seemingly expressing his displeasure with Stewart over a bumping incident during the race at Canandaigua Motorsports Park.

Ward died of blunt force trauma. Ontario County Sheriff Philip Povero said the autopsy was completed Monday.

Authorities questioned Stewart on Saturday night and went to Watkins Glen to talk to him again Sunday. Povero said Monday there were no plans “at this time” to talk to Stewart again.

There is no timetable to complete the investigation.

Povero said there is nothing in the inquiry that supports criminal conduct or probable cause. No charges have been filed.

The sheriff renewed a plea for spectators to turn over photos and videos of the incident.

Investigators were reconstructing the accident and looking into everything from the dim lighting on a portion of the track to how muddy the surface was, as well as if Ward’s dark firesuit and helmet played a role in his death, given the conditions.

Stewart’s status for the next Sprint Cup Series race, the Pure Michigan 400 on Sunday in Brooklyn, Mich., is uncertain.

Stewart “will have as much time as he needs to make that decision,” said Mike Arning, director of communications for the Stewart-Haas Racing team. “It is still an emotional time for all involved, Tony included. He is grieving, and grief doesn’t have a timetable.”

The crash raised several questions: Will Ward’s death cause drivers to think twice about on-track confrontations? Did Stewart try and send his own message by buzzing Ward, only to have his risky move turn fatal? Or did Ward take his life into his own hands by stepping into traffic?

David Weinstein, a former state and federal prosecutor in Miami who is in private practice, said it would be difficult to prove criminal intent on the part of Stewart.

Some short-track executives say they believe Ward’s death will lead to new safety rules in terms of drivers staying in their cars.

“All of the people in the industry will try to learn from this,” said Clint Elkins, co-owner of Carolina Speedway in Gastonia, N.C.