On the afternoon of February 19, 2008, a bus from the Lakeview School District in Cottonwood was taking 28 students home for the day.
As the school bus traveled south on Highway 23, a minivan heading east on a county road smashed into it at an intersection. The bus flipped on its side and came to rest on a pickup truck.
Karen Mahlum of Sacred Heart was only a quarter mile away when the accident happened. She saw a cloud of dirt fly up into the air, and then she spotted scraps of metal strewn on the highway.
The day after the crash Mahlum told Minnesota Public Radio that when she stopped to help, the driver handed children to her from an escape hatch on the bus.
"Some of them had a little blood on them. A lot of them were crying that their head hurt, their arms. They were crying that they wanted their mommies and daddies," said Mahlum. "They had a sister or brother on the bus that they wanted to get off the bus. A lot of real emotional stuff."
Four children, ranging in age from 9 to 13, died in the crash. Two of them were brothers.
Cottonwood, a town of about 1,100 people, reeled in the aftermath.
A day after the crash a few hundred people turned out for a mass at the local Catholic church.
During his sermon, Rev. Paul Hadusek asked a question that seemed to have no answer.
"Why, Lord? Why this?" Hadusek asked. "I don't know if anyone of us, me included, would accept any answer from the Lord as a right answer. I don't know."
While the town of Cottonwood mourned, investigators worked to determine who caused the accident.
A woman who was pulled from behind the wheel of the van gave her name as Alianiss Nunez Morales.
Prosecutors charged her with four counts of vehicular homicide and more than a dozen counts of criminal vehicular injury.
That same day federal immigration agent Claude Arnold announced the woman had lied about her identity.
"Our agents developed probable cause that Ms. Nunez Morales is in the country illegally and that is not her true identity," Arnold.
Federal officials said Morales was actually Olga Franco of Guatemala, who didn't have a valid driver's license.
News of Franco's immigration status heightened the debate over illegal immigration in some Minnesota communities.
In Willmar, a town that's struggled with the issue of immigration in recent years, some saw the crash as a reason to crack down on illegal immigration.
Marlene, a Willmar resident who wouldn't give her last name, said Franco's immigration status made the tragedy of the bus crash even worse.
"There are a lot of people angry over this," said Marlene. "It just made me sick when I think of the grief that those families went through, because this woman was in the country and shouldn't have been."
But Willmar's Latino community cringed at that talk.
Edel Fernandez, Director of Multicultural Affairs at Willmar's Ridgewater College, wondered why the fatal bus crash was mixed up with the topic of illegal immigration.
"Because of the political world we live in, this has become more of an issue, and actually people pay more attention to this," said Fernandez. "It is unfortunate that we have lost some lives, and that should be the main issue, whether the person that did it is from here, from Mars or from wherever."
The town of Willmar, which is about 50 miles from the crash site, has now become even more a part of this case. Judge David Peterson moved the location of the trial from Marshall to Willmar in June.
Defense attorneys are going to argue that Franco wasn't driving the van.
St. Paul attorney Manuel Guerrero represents Franco. At an April court hearing, Guerrero told reporters that even though Franco was found pinned behind the steering wheel after the accident, he thinks Franco's boyfriend was driving.
"I think that it was a matter of her being thrust in that position upon the impact of the van with the bus," said Guerrero. "Since she didn't have any seat belts on, and he didn't have any seat belts on, she was thrown over in that direction, and then she righted herself by grabbing the steering wheel and pulling herself up."
Franco's boyfriend has been identified as Francisco Mendoza, a Mexican national who hasn't been seen since the crash.
Defense attorney Guerrero said in May that several people saw Mendoza fleeing the site of the crash, and that a co-worker picked him up and drove him away.
"The driver who carried him away from the scene of the accident came forward," said Guerrero. "He saw the publicity and talked with his pastor. The pastor suggested that he should come forward and contact the police."
Guerrero said Franco's claim was bolstered when at a May 15th hearing a federal agent confirmed that both Franco and Mendoza were in the van.
And in June, Guerrero said DNA tests found blood on both the van's passenger and driver airbags. Guerrero said tests from the Minnesota Bureau of Criminal Apprehension show blood on the airbags came from an unidentified male.
Guerrero is using what's called the alternative perpetrator defense, an effort to raise reasonable doubt in jurors' minds that Franco was the one driving the minivan.
According to University of Minnesota Law professor Richard Frase, one factor that will make that defense difficult is that Franco's boyfriend hasn't been found.
"The fact that the supposed alternative perpetrator hasn't been located, can't be interviewed by both sides, can't be called as a witness unless they get found at the last minute certainly weakens the defense claim because there's just not that direct evidence from the person," Frase said.
Judge David Peterson has put a gag order in place throughout the trial's entire proceedings, so attorneys and witnesses won't be able to talk publicly about the case outside of court.
Court officials say the trial could last up to three weeks.