Kathy Griffin’s photograph depicting her holding up a fake, bloodied decapitated head meant to resemble President Donald Trump is now the subject of a United States Secret Service investigation, according to a report.Law enforcement sources told TMZ that the Secret Service has launched an investigation into “the circumstances surrounding the photo shoot.”On Tuesday, the federal agency took to Twitter and seemingly acknowledged Griffin’s photo, which has been messaged directly at the Secret Service by numerous social media users.“On it! @SecretService has a robust protective intelligence division that monitors open source reporting & social media to evaluate threats,” the agency tweeted Tuesday afternoon.