Stokes said he was "completely shocked" by the arrest of Byers, who he said had enjoyed success as a model and was also a personal trainer who co-owned a gym.
He said the model had texted him on Tuesday to let him know he was moving to New York to live with his girlfriend.
"He said life was good and he was happy and that things had changed," Stokes told the Greenwich Time.
"When we do photoshoots we play up the badboy element, that's the appeal, but I guess inside a lot of these models there is a real bad boy. But it surprises me with David, because he had a good upbringing.
"I know he's an unusual guy, but bank robbery doesn't seem like his thing. He's always been so decent and respectful with me."
Stokes described Byers as a popular model who appeared on the cover of one of his books. He has also appeared on the covers of three romance novels.
Byers reportedly had a handgun tucked into his waistband when he was arrested but did not put up a struggle, police said.
The Greenwich Police Department has requested that he be extradited to Connecticut, where he faces one count of first-degree robbery, two counts of third-degree robbery, two counts of larceny, and one count of reckless endangerment.
Bail is set at US$200,000.
