(SANTE FE, TEXAS)–One person, reportedly a male who federal officials believe to be a student, is in custody, and another person has been detained, Harris County Sheriff Ed Gonzalez tweeted. Nearly a dozen people have been shot to death and many others were injured, including police officers . “This morning an incident occurred at the high school involving an active shooter. The district has initiated a lockdown. We will send out additional information as soon as it is available,” the school district posted on Facebook. One student told KTRK, a Houston TV station, that the gunman entered her art class around 7:30 a.m. and began shooting. She said she could not identify the shooter because she was in a hurry to escape the classroom. Student Damon Rabon told CBS News that he was in a classroom one door away from the shooting. He said he saw the shooter in the school hallway. “He had a black trench coat on, a sawed-off shotgun with a pistol grip and I think something sharp on this chest,” he said. He added that his teacher pulled the fire alarm “to let everyone know to get out of the school.” A man holding a large American flag, carrying a gun, was at the scene of the Sante Fe High School shooting in Texas and said “Make America Great Again”. He was speaking to local KHOU-TV reporters near the scene where there are possibly multiple fatalities. The man said he was there to “offer support” but it was unclear what kind of support he was offering by echoing US President Donald Trump’s now-famous slogan. “‘God bless ya’ll’ will go a long way..right now,” the man said before walking away when it was clear he was openly carrying a pistol on his right hip, clipped to his shorts. An unidentified then appeared on camera, chastising the first man. Live updates as ‘Multiple fatalities’ reported after gunman open fire. Standing near a petrol station, the second man said to reporters “that’s not what America needs. America needs prayers,” adding that though he supports Second Amendment rights to carry firearms, he thought it was “an embarrassment” that the flag-carrier showed up at the high school “crime scene” while openly carrying a gun. He said he hoped “they would get him,” perhaps implying he hoped police would arrest him. “This idiot is walking down the street with a damn pistol on the site where we just had kids get shot,” the second man said. “I have guns…but this idiot is walking down here saying ‘Make America Great Again,’ that’s not what America needs. America needs prayers, we don’t need this crap,” he said animatedly.