The U.S. Office of Special Counsel released a report Monday
detailing Castro's admitted violation of the Hatch Act, which prohibits federal employees from taking sides in politics while acting in their official capacity.
Castro's in trouble for expressing his support for Clinton's presidential race and for saying Donald Trump doesn't have what it takes to sit in the Oval Office. He's allowed to make political statements on his own time, but not while engaging in official HUD business.
Castro made the comments that have him in hot water during an 18-minute interview on April 4 with Yahoo News' Katie Couric, who introduced Castro as the former mayor of San Antonio, the keynote speaker at the 2012 Democratic Convention, the secretary of HUD and as a potential vice presidential candidate.
According to the investigative report, the interview started with Castro talking about ConnectHome, an initiative to expand internet access to families living in public housing. However, about seven minutes into the interview, Couric asked Castro about his endorsement of Clinton.
"Now taking off my HUD hat for a second and just speaking individually, it is very clear that Hillary Clinton is the most experienced, thoughtful, and prepared candidate for President that we have this year," Castro said.
When Couric asked Castro what he feared most about a Trump presidency, Castro said Trump isn't prepared to be president because he doesn't understand leadership or the basic functions of government.
Adam Miles, a spokesman for the U.S. Office of Special Counsel, said the report was sent to Obama's office. Since Castro was appointed by President Barack Obama in 2014, it's up to the president to determine whether to dish out any punishment, Miles explained.
"When, during the live broadcast, I received the direct questions regarding specific candidates, I used the inelegant phrase 'taking off my HUD hat' to indicate my intention to respond in my personal capacity, and not as a representative of HUD," Castro told investigators.
He goes on to say that his intention was to avoid blurring his personal and professional role, but understands it may not have been obvious to viewers. That might be because the interview was filmed in HUD's Washington D.C. broadcast studio with the HUD logo emblazoned behind him.
However, if Castro is treated like the last Obama appointee to violate the Hatch Act, he's likely not going to face any punishment.
In September 2012, as Obama faced off against Republican Mitt Romney, the U.S. Office of Special Counsel found that then Health and Human Services Secretary Kathleen Sebelius violated the rule while speaking at a Human Rights Campaign event. Sebelius urged people to vote for Obama during her speech. The White House didn't punish Sebelius, FOX News reported at the time
A federal investigative agency found that U.S. Department of Housing and Urban Development Secretary Julián Castro was campaigning for Hillary Clinton while conducting official business.