An argument over texting in a US cinema ended with a retired police officer shooting dead the man sitting in front of him,.

The killing came after Curtis Reeves, 71, asked 43-year-old Chad Oulson to stop texting.

Reeves and his wife were sitting behind Mr Oulson and his wife. Mr Oulson told Reeves he was texting his three-year-old daughter.

Witness Charles Cummings who was in the Florida audience said: "Somebody throws popcorn. I'm not sure who threw the popcorn. And then bang, he was shot."

"It ended almost as quickly as it started," said a sheriff's spokesman. An off-duty officer detained Reeves until police arrived.

Mr Cummings, who had blood on his clothes, the show was still in the preview section when the two couples started arguing.

Mr Cummings said the men started raising their voices and popcorn was thrown. Police said Reeves took out a gun, Oulson's wife put her hand over her husband and Reeves fired his weapon, striking Nichole Oulson in the hand and her husband in the chest.

"I can't believe people would bring a pistol, a gun, to a movie," Mr Cummings said. "I can't believe they would argue and fight and shoot one another over popcorn. Over a cellphone."

Mr Cummings said Mr Oulson fell onto him and his son.

The film showing was Lone Survivor.