The leader of the Democratic team prosecuting Donald Trump's impeachment trial became emotional on Tuesday as he recalled his daughter and son-in-law hiding in fear during the US Capitol riot on January 6. Jamie Raskin,a constitutional law expert now in his third two-year term representing parts of Maryland, defended the legality of impeachment charges against a former president. When he invited his family to see the January 6 joint session of Congress to certify Joe Biden's presidential election victory, Mr Raskin was also mourning the death of his son, 25, on December 31. He said his daughter, 24, asked whether they would be safe visiting on January 6, after hearing of plans by thousands of Trump supporters to descend on Washington to try to stop the routine proceeding. "I told them, of course it should be safe. This is the Capitol," Mr Raskin said as he wrapped up his opening argument. But when the mob invaded the building in a violent assault that left a Capitol Police officer and four other people dead, his daughter, Tabitha, and other family members were forced to huddle in an office near the House of Representatives. Mr Raskin said that when he was reunited with his daughter and son-in-law, he apologised and promised things would be better on their next visit. "And you know what she said? She said, 'Dad, I don't want to come back to the Capitol'," he said. The Senate's 100 members paused from taking notes and fiddling with papers on their desks, watching Mr Raskin as he spoke tearfully of his daughter's fear. At times barely able to speak, he wrapped up his opening statement to the Senate by saying: "Of all the terrible things I saw ... that one hit me the hardest. "That and watching someone use an American flagpole, the flag still on it, to spear and pummel one of our police officers."