Curtis Reeves, 71, allegedly shot Chad Oulson, 43, in the chest and Nichole Oulson, Chad's wife, in the hand as she attempted to block the bullet. The shooting occurred at about 1:30 p.m. approximately 22 miles north of Tampa.
Reeves, a retired Tampa police officer, was at the movie with his wife. Reeves asked the couple sitting in front of him several times to stop texting during previews before the main attraction, "Lone Survivor."
Reeves then left the theater and returned, according to police, and Chad Oulson asked him if he reported the phone use to theater management. Police said that provoked an argument, ending with the shooting.
"The victim was on his cellphone, he was texting. We believe he was making some kind of noise. This noise led to an altercation," Pasco County Sheriff Chris Nocco said. "During that altercation, the suspect decided to pull out a .380 and he shoots the victim."
"Somebody throws popcorn. I'm not sure who threw the popcorn," said Charles Cummings, who was in the Grove 16 Theater. "And then bang, he was shot."
An off-duty Sumter County sheriff's deputy in the theater subdued Reeves and disarmed him, holding him until officers arrived. Two nurses in the theater performed CPR on Chad Oulson. About 25 people were in the theater at the time of the shooting.
The Oulsons were airlifted to Tampa General Hospital, where Chad Oulson was declared dead of his wound. Nichole Oulson was treated for her injury, which was not considered life-threatening.
Reeves was charged with second-degree murder. Police said Reeves and the Oulsons did not appear to know each other.
Tampa Police said Reeves is a former captain who retired 20 years ago after helping to create the department's tactical response team. After he retired, Reeves worked security for the Busch Gardens theme park and was on the board of a neighboring county's Crime Stoppers organization. Reeves' son also is a Tampa officer, police said.
ABC News and The Associated Press contributed to this report.