WASHINGTON (AP) — Looking to undermine Democratic rival Joe Biden, President Donald Trump's campaign is pushing a familiar line of attack: unverified allegations about Biden's son and his foreign business ties.

But reporting in the New York Post, and the emergence of a man who says he worked with Hunter Biden, have raised more questions than answers, including about the authenticity of emails at the center of the story.

The renewed allegations trace back to Trump lawyer Rudy Giuliani, who has repeatedly pushed unfounded claims about the Bidens. Even if the emails in the Post are legitimate, th...