Story highlights At least nine others injured at auto auction in Billerica, Massachusetts

Massachusetts State Police: "All evidence ... at this time suggests an accidental cause"

(CNN) Three people were killed and at least nine others injured Wednesday after an SUV suddenly sped forward and ran down customers at an auto auction in Billerica, Massachusetts, north of Boston.

Two people have life-threatening injuries, Middlesex District Attorney Marian Ryan said. A family member of one of those killed was not injured but was taken to a local hospital due to stress, she said.

Ryan said preliminary information suggests it was an accident. She said the driver was a Lynnway Auto Auction employee in his 70s. He was not hospitalized.

"At this point, there is no evidence or information to suggest the incident was caused by an intentional or terrorist act. All evidence and information at this time suggests an accidental cause," the Massachusetts State Police tweeted.

No evidence of attack, intentional act in Billerica incident. Investigation ongoing. https://t.co/z164qn13wM — Mass State Police (@MassStatePolice) May 3, 2017

Several hundred employees and customers had gathered for the weekly auction that generally draws a crowd, Ryan said. On its Facebook page, Lynnway Auto Auctions said it consigns more than 2,000 cars for sale at 8:40 a.m. every Wednesday.

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