As the test continued, "Mrs. Witherspoon began to hang out the window and say that she did not believe that I was a real police officer. I told Mrs. Witherspoon to sit on her butt and be quiet," Trooper First Class J. Pyland writes.
Toth, 42, was then placed under arrest. He was charged with driving under the influence and failure to maintain the lane.
At that point, the report says, Witherspoon got out and asked the trooper what was going on. After being told to return to the car, she "stated that she was a 'US Citizen' and that she was allowed to 'stand on American ground,'" the report states.
The trooper then began to arrest Witherspoon. The report says Witherspoon was resistant at first but was calmed down by her husband.
Toth and Witherspoon were then taken to jail.
News of the arrest broke shortly before Witherspoon arrived on the "Mud" red carpet.
"I can't say anything because I don't know," said director Jeff Nichols. "I literally — the first guy on the press line to say something was the first time I heard about it so I gotta go figure it out."
Matthew McConaughey, who plays the lead role in "Mud" and is represented by Toth, said "I'm not going to comment on that because it's too fresh."
AP writers Sandy Cohen in Los Angeles and Lauri Neff in New York contributed to this report.