President Trump and his family arrived back in Washington, D.C. on Sunday evening after spending the weekend at his Mar-a-Lago retreat in sunny Florida. The president was seen boarding Air Force One in Palm Beach with his wife, First Lady Melania Trump, and their 13-year-old son, Barron. Also making an appearance was Ivanka Trump, his daughter; her husband, Jared Kushner; and their children, Theodore, Joseph, and Arabella. President Trump and First Lady Melania Trump walk along the South Lawn of the White House on Sunday The first couple disembarked from Marine One after it landed on the South Lawn. The Trumps were returning to the capital after spending the weekend at the Mar-a-Lago estate in Palm Beach, Florida The president was joined by his in-laws, Amalija Knavs (left) and Viktor Knavs (right). Last year, the first lady's parents became American citizens While Ivanka was tending to Theodore, her husband held the hands of the couple's other two children, Arabella and Joseph. The president's youngest son, Barron Trump, was also seen boarding Air Force One with his father. The 13-year-old Barron has not made many public appearances since his father became president in January 2017. After landing at Joint Base Andrews following their Florida weekend, the Trumps boarded Marine One for the short flight to the White House. The president and first lady were seen deplaning from Marine One. Earlier on Sunday, the president's youngest son, Barron Trump, was also seen boarding Air Force One with his father Barron Trump is seen left following his parents as they board Air Force One at Palm Beach International Airport on Sunday The president waves as his 13-year-old son, Barron, walks into Air Force One, which will take them back to the Washington, D.C. area The Trumps are seen above disembarking Air Force One after it landed at Joint Base Andrews in Maryland on Sunday Ivanka Trump, the president's daughter and senior adviser, holds her son Theodore's hand as they walk from Air Force One at Joint Base Andrews While Ivanka was tending to Theodore, her husband, Jared, was escorting the couple's other two children, Arabella and Joseph (who is behind his father in the photo on the right) Ivanka has a tender mother-son moment with Theodore on the tarmac of Joint Base Andrews in Maryland on Sunday The Kushners joined the Trumps for their relaxing weekend at Mar-a-Lago after an eventful week in the nation's capital Ivanka Trump stands on the tarmac with her son Theodore at Joint Base Andrews in Maryland on Sunday evening In tow were the first lady's parents, Viktor and Amalija Knavs. Last year, the Knavs took the oath of citizenship and became American citizens. Melania Trump is America's first foreign-born first lady. Her family is from Slovenia. It is rare for the president's in laws to join him and his family, though it has happened before. Trump's Mar-a-Lago weekend came after a triumphant week during which his attorney general released a summary of the Mueller report which cleared him and his campaign of colluding with the Russian government. The bombshell announcement led Trump and his supporters to declare victory, claiming that he was fully vindicated. Trump on Sunday called for an investigation into how the special counsel probe against him and his campaign began, continuing a drum beat against Robert Mueller's look into collusion and obstruction of justice. 'Everybody is asking how the phony and fraudulent investigation of the No Collusion, No Obstruction Trump Campaign began. We need to know for future generations to understand. This Hoax should never be allowed to happen to another President or Administration again!,' he wrote on Twitter on Sunday. Trump has railed against the investigation since it ended and cleared him and his campaign of any collusion with Russia in the 2016 election. President Donald Trump called for an investigation into how the special counsel probe against him and his campaign began Trump has railed against special counsel Robert Mueller's probe ended Trump tweeted: 'Everybody is asking how the phony and fraudulent investigation of the No Collusion, No Obstruction Trump Campaign began. We need to know for future generations to understand. This Hoax should never be allowed to happen to another President or Administration again!' Acting White House Chief of Staff Mick Mulvaney said Sunday it was important to find out what went wrong around Mueller's investigation and the media reports of the past 22 months. 'We need to figure out what went wrong with the Mueller report, why - in all fairness to your network, why the media got it so wrong for so long,' he told CNN's Jake Tapper on "State of the Union" on Sunday. 'How did the media get it so wrong? I think the president is just venting the same frustration a lot of people had when the Mueller report came out, and it turned out exactly like he said that it would,' he said. He said the White House has not read the full report, merely Attorney General William Barr's summary that went to lawmakers. 'I have read the Barr summary, which is what everybody else has read,' Mulvaney said. Trump said on Friday he is on board with Barr's decision to release the nearly 400-page Mueller report – minus several categories of redactions that are already drawing scrutiny. 'I have great confidence in the new attorney general, if that's what he'd like to do,' Trump told reporters at his Mar-a-Lago club. 'I have nothing to hide,' the president said. Then Trump went off on yet another attack against the Mueller probe, the product of which Barr would be releasing following a redaction process, according to a new letter from the attorney general. 'This was a hoax. This was a witch hunt. I have absolutely nothing to hide. And I think a lot of things are coming out with respect to the other side,' Trump said. The comment was a veiled reference to Democrats and other critics who have been set back by summary findings that Mueller did not find evidence that his campaign conspired with the Russian government. 'I have nothing to hide,' President Trump said Friday. He was speaking to reporters at Mar-a-Lago alongside outgoing Administrator of the Small Business Administration Linda McMahon By Friday evening, Trump took his attacks on Mueller online, casting the prosecutor who Trump earlier bragged 'totally exonerated' him as a partisan idolized by the 'Radical Left.' 'Robert Mueller was a Hero to the Radical Left Democrats, until he ruled that there was No Collusion with Russia (so ridiculous to even say!). After more than two years since the 'insurance policy' statement was made by a dirty cop, I got the answers I wanted ...' Trump wrote, referencing an FBI email uncovered through an Inspector General's investigation 'The problem is,' Trump followed up in another tweet, 'no matter what the Radical Left Democrats get, no matter what we give them, it will never be enough. Just watch, they will Harass & Complain & Resist (the theme of their movement). So maybe we should just take our victory and say NO, we’ve got a Country to run!' he wrote. Earlier Friday afternoon, Barr told the chairmen of the House and Senate Judiciary Committees that he expects to release Mueller's final report in the next two weeks, and that he will testify publicly about it in early May. Mueller completed his investigation on March 22. The event that sparked the $25 million, 22-month probe was a concern from federal officials that there was a tie between Trump's campaign and hacked emails from Democrats that appeared on Wikileaks. The kickoff began when WikiLeaks released hacked emails from the Democratic National Committee and Hillary Clinton campaign manager John Podesta in July 2016. After that event, an Australian diplomat based in London tipped off American authorities that a Trump campaign official, George Papadopoulos, had told him a few months earlier that the Russians had the stolen emails. Concerned the Trump's campaign had been infiltrated by foreign agents, the FBI began its probe, allegedly securing the help of a Cambridge professor to meet with some of Trump's advisers. The Justice Department secured warrants from a secret court that handles foreign intelligence cases, giving it permission to spy on Trump campaign adviser Carter Page past the point of the November election. President Donald Trump Attorney General William Barr (left) and Special Counsel Robert Mueller (right) A turning point came when President Trump fired FBI James Comey on May 9, 2017. He later asked a friend to leak details from his memos of meetings with Trump, to a friendly reporter, in the hope that it would lead to the appointment of a special counsel. Democrats were outraged and started a special counsel drumbeat. With Attorney General Jeff Sessions on the sidelines because he had been a foreign policy adviser to Trump's campaign, his deputy Rod Rosenstein appointed Robert Mueller to the job eight days later. Mueller's investigation was the subject of numerous news reports, which depicted a colorful cast of characters who wormed their way into Trump's campaign and put the new administration on the defensive. In the end, Mueller concluded that neither President Trump nor his campaign colluded with Russians in order to improve his chances of beating Democrat Hilary Clinton. The special counsel did not draw a conclusion 'one way or the other' on whether the president obstructed justice, according to the findings, but left that decision to Attorney General William Barr, who decided not to pursue them. All rights reserved for this news site dailymail and under his responsibility