During a court hearing in Marshall, a federal immigration agent confirmed that Franco's boyfriend was in the van when it struck the school bus.
Investigators are still searching for Franco's boyfriend, Francisco Sangabriel-Mendoza, but they believe he may have left the country.
This mystery figure has become a central character in the Feb. 19 bus crash which killed four students from the Lakeview School District, based in the southwest Minnesota community of Cottonwood.
Federal Immigration and Customs Enforcement Agent Jeremy Christenson today testified he's conducted interviews which confirm that Sangabriel-Mendoza was in the van on the day of the crash.
After the hearing, Olga Franco's attorney said several people saw the boyfriend running away from the accident scene along a county road. Defense attorney Manuel Guerrero said a coworker picked up Sangabriel-Mendoza 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."
No one identified the coworker by name. Guerrero says the coworker came forward in late April, about two months after the fatal crash.
Guerrero says Sangabriel-Mendoza and the coworker were employed at a cabinet factory in Cottonwood.
He says Sangabriel-Mendoza was thrown from the van on impact, and suffered a back injury in the crash. He says the boyfriend may have pulled Olga Franco into the driver's seat before he left.
In the past, Guerrero has also said it's possible the force of the impact threw Franco into the driver's seat. He says investigators have been able to question people who knew the boyfriend.
"It's my understanding that the ICE agents have also talked to members of the boyfriend's family," said Guerrero.
Guerrero says Sangabriel-Mendoza's family and friends told investigators that after the accident, he first went back to the town where he was living, Minneota.
From there, it's believed he spent time in Willmar before leaving Minnesota for Chicago. Guerrero says after Chicago, the boyfriend's trail disappeared.
Federal officials say Sangabriel-Mendoza and Olga Franco were in the country illegally. Both face federal charges of identity theft.
Defense attorney Guerrero has tried to convince the judge in the case to throw out two apparently contradictory interviews Franco gave investigators soon after the accident.
In the first interview a few hours after the accident, Franco appeared to say that she was driving the van. District Court Judge David Peterson has ruled that statement will be allowed into evidence. Guerrero is challenging that decision.
Judge Peterson threw out a second interview conducted two days after the crash. In that interview, Franco said her boyfriend was driving the van. The judge says investigators unconstitutionally continued to question her after she asked for a lawyer.
Defense attorney Guerrero has also asked that Olga Franco's trial be moved out of Marshall. In court documents, he says media and Internet reports about the bus crash make it nearly impossible to find an impartial jury in Lyon County.
In Guerrero's words, most people in the area feel that convicting Franco is only an "annoying formality."