FRESNO (CBS SF) _ Federal authorities say they have dropped charges against a hunter accused of staring a massive wildfire that burned part of Yosemite National Park.

Prosecutors said Friday that two key witnesses have unexpectedly died since the indictment was handed down last year against Matthew Emerald.

The 33-year-old California man was accused of starting the 2013 blaze called the Rim Fire that burned for two months, scorching 400 square miles and causing $125 million in damage.

Authorities say one witness who had talked with Emerald shortly after being rescued by helicopter, died in February in a workplace accident. The second witness, a helicopter pilot, died of a heart attack.

Prosecutors say that without testimony from the two, they don’t believe they can prove the case beyond a reasonable doubt.

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