A woman who initially lied about her identity and still denies driving a van that slammed into a school bus, killing four children, was sentenced Wednesday to nearly 13 years in prison.

Olga Marina Franco Del Cid was convicted in August of 24 charges, including four counts of criminal vehicular homicide in the Feb. 19 crash involving a bus from Lakeview School near the southwest Minnesota town of Cottonwood.

Lyon County Attorney Rick Maes said he had hoped for a tougher sentence, and acknowledged the case affected him on a personal level because he has five children who regularly ride a school bus.

"This is a very horrific incident that occurred and is something that didn't need to occur," he said. He noted that with good behavior, Franco's prison time could be reduced to eight years and four months.

"That doesn't seem like a lot of time for what happened," Maes said.

Franco's attorney, Manuel Guerrero of St. Paul, said he plans to appeal her conviction and didn't agree with her sentence. "I don't think it was fair," he said. "I think it was excessive. It didn't fit the crime."

He said Franco has little understanding of the justice system and said she was a "little confused about what's going to happen to her now."

Franco was extricated from the driver's seat of the minivan, which hit the school bus after barreling through a stop sign. But her attorneys tried to show during her trial that Franco's boyfriend was driving, fled the scene and hasn't been seen since.