A Brooklyn jury convicted a Philadelphia TV memorabilia collector yesterday of stalking “Law & Order: Criminal Intent” star Kathryn Erbe after prosecutors argued that his romantic obsession with her turned to anger when she ignored his letters.

The most damning evidence in the federal court trial was a doctored photograph of Erbe’s 14-year-old daughter posted on MySpace.

Charles Nagel denied posting the photo and claimed his own young daughter and her teenage friend were responsible. But the jury appeared to reject this explanation, convicting the self-described “fanboy” after 4½ hours of deliberation.

The panel convicted him of using the Internet and mail to stalk the actress but cleared him of traveling across state lines to stalk her.