Shareholding

One of the person is director as well as shareholder in a company. He resigned from the post of directorship and mentioned in resignation letter that " All my shareholding back to company. After this my shareholding with the company will be zero".  But no share transfer deed is executed for this. In the annual return he is not a shareholder. Company has never issued share certificates. 

Today whether this person is shareholder in the co. or not. If yes then how it can be proove.