CHP has completed a 10-month investigation into a fiery crash on Highway 101 that claimed the lives of five family members and badly burned a 5-year-old boy, recommending that the driver who struck their car face criminal charges.

CHP Officer Barbara Upham said Wednesday the report had been turned over to the Sonoma County District Attorney?s Office. But she would not detail what charges authorities have recommended for Ryan Karr, whose Mitsubishi coupe smashed into the back of the Honda Civic during the late-afternoon commute on Jan. 19.

?That?s up to the D.A.?s office to make the final determination,? Upham said.

At the crash scene, rescuers pulled kindergartner Christian Flores Carlos of Windsor from the burning vehicle.

But the 23-year-old driver, Edith Carlos Medina, his mother, suffered fatal injuries. So did the boy?s grandmother, Maria Lopez Camacho, 54; brother, Fernando Flores Carlos, 7; and aunts Almadelia Mendera-Basurto, 16, and Carmina Solorio, 23.

Solorio was from Mexico. The others lived in Windsor.

The multi-agency investigation involved coroner?s reports, accident reconstruction, testing of a blood sample that Karr voluntarily submitted, and numerous interviews with drivers, witnesses and citizens who tried to help the victims, Upham said.

With ?something as extensive as this, involving multiple fatalities, the investigation becomes much more thorough and the interviews much more extensive,? she said. ?There were people on scene we could never identify, but we pursued every avenue in terms of identifying witnesses on the scene.?

After months of hospitalization in Sacramento, Christian has returned to kindergarten in Sonoma County and is being cared for by an aunt, according to Santa Rosa attorney Patrick Emery, who represents the victims? family.

He said he?s eager to review the CHP?s findings on their behalf.

?We all see significant rear-end impacts on the freeway every day, but it?s very rare that a car virtually explodes the way this one did,? Emery said, referring to the Civic. ?We want to figure out what happened here.?