That's just it... I don't know if there is another way other than at work where people can get involved in betting on games. I don't know how large the stakes get if organized crime also runs such betting pools. I know nothing about gambling other than I played a slot machine one time and I didn't enjoy it so I have no experience and less knowledge than probably most people about the subject.
But, if James had trouble staying away from games like this and Denise was afraid her family would disapprove, it might be something she didn't want them to know about so they really don't know about it. I'm not trying to blame James at all. Millions like to play a bet now and again and a lot of us buy lottery tickets. It's a matter of degree of participation. But, like Very Veritas said, maybe it was just a question of getting in over his head just a little bit at a time with the wrong people.
And, if any of James's friends or co-workers do know, they probably are keeping quiet because of what happened to James and his family.