(Newser) – The Donald Trump Jr. Russia email controversy will, according to a US official who spoke to CNN, be probed by Justice Department Special Counsel Robert Mueller's investigators. The investigators will look into Trump Jr.'s emails with a Russian lawyer during the 2016 US presidential election as part of its broader probe into Russian meddling with the election, the sources say. President Trump spoke out for the first time on the controversy today, as critics said it may be a "smoking gun" since the lawyer was allegedly going to give Trump Jr. dirt on Hillary Clinton. (Read more Donald Trump Jr. stories.)