She is 25 and should be making up her own mind, however it seems you are leaving out something about this relationship, or you would have let us know what's going on with her that she would not just leave town and marry you.
If I was here parents I would not want her to marry Harold if she does not love him, I would not want her to marry you because you're not a christian. This said I would recognize that she is 25 and can make up her own mind. I would not love her less because she married a non christian, I would appeal to her christian heritage that she would ask you to go to church with her. After that there would not be much I could do except to love you as a son-in-law. Before you call the police about Harold you should talk with her, if you do not you could ruin your relationship with her. I know how you feel I went through the same thing, result, fell in love with another and we have been married for 33 years, so if you lose out to Harold all is not lost, there is another out there for you.
If I was here parents I would not want her to marry Harold if she does not love him, I would not want her to marry you because you're not a christian. This said I would recognize that she is 25 and can make up her own mind. I would not love her less because she married a non christian, I would appeal to her christian heritage that she would ask you to go to church with her. After that there would not be much I could do except to love you as a son-in-law. Before you call the police about Harold you should talk with her, if you do not you could ruin your relationship with her. I know how you feel I went through the same thing, result, fell in love with another and we have been married for 33 years, so if you lose out to Harold all is not lost, there is another out there for you.
God loves those who believe and those who do not and the same goes for me, you have no choice in this matter. That puts the matter of total free will to rest.