An Uber driver sparked a small bushfire. Feds say it became a deadly blaze.

Jonathan Rinderknecht faces up to 45 years in prison as his federal trial begins in Los Angeles.

When a dry spark catches, a whole community can burn.

Families in Los Angeles learned this the hard way when a tiny fire grew into a nightmare that took twelve lives.

WHAT HAPPENED

Federal prosecutors say Jonathan Rinderknecht was working as an Uber driver last year. They claim he started a bushfire in the Pacific Palisades area of Los Angeles.

That small fire did not stop. It burned for six days and grew into one of the most destructive fires in the city's history, destroying homes and killing 12 people.

Now, Rinderknecht faces a federal trial. Jury selection starts on Monday for charges including arson and destroying property.

WHAT THE EVIDENCE SHOWS

12 people died in the fire.

• The fire burned for 6 days before becoming one of the most destructive in Los Angeles history.
• The suspect was working as an Uber driver when the fire started.
• He faces up to 45 years in prison if convicted.
• The charges include destruction of property by fire and arson.

THE BIGGER QUESTION

How does a simple ride-share trip turn into a deadly disaster?

This case forces us to look at how quickly our dry hills can burn, and how one person's quick mistake can ruin hundreds of lives.

THE OTHER SIDE

Rinderknecht pleaded not guilty. His defense lawyers say he denies setting the fire on purpose and should not be held responsible for how the flames spread.

Because prosecutors must prove he acted on purpose to get an arson conviction, this defense could raise real doubts for the jury.

WHAT HAPPENS NOW

The trial will bring back painful memories for the families who lost their homes and loved ones.

It also puts a spotlight on safety rules for gig workers who drive through dry, high-risk hills.

WHAT WE STILL DON'T KNOW

1. What exactly did Rinderknecht do that sparked the first bushfire?
2. Was there any delay in the emergency response during those first six days?
3. How will Uber change its safety rules for drivers in dry areas after this trial?

SOURCE NOTE

All charges are allegations - Jonathan Rinderknecht is presumed innocent until proven guilty. This report uses information from ABC News and court filings.