President Trump began the weekend believing that something good had just happened to him. An indictment leveled against 13 Russians for interfering with the 2016 election had not accused him or anyone around him of wrongdoing. "No collusion" was his refrain.

But once ensconced at his Florida estate on Friday, Mr. Trump, facing long hours indoors as he avoided breezy rounds of golf after last week's school shooting a few miles away, began watching TV.

The president's mood began to darken as it became clearer to him that some commentators were portraying the indictment as nothing for him to celebrate, according to three people with knowledge of his reaction. Those commentators called it proof that he had not won the election on his own, a particularly galling, if not completely accurate, charge for a president long concerned about his legitimacy.

What followed was a two day Twitter tirade that was unusually angry and defiant even by Mr. Trump's standards. In his tweets on Sunday, Mr. Trump sought to shift the blame to Democrats for Russia's meddling, saying that President Barack Obama had not done enough to stop the interference.

The president denied despite the ample evidence to the contrary that he had ever suggested that Moscow might not have been involved. He called Representative Adam B. Schiff of California, the top Democrat on the House Intelligence Committee, a "monster." And he asserted that the Russians were "laughing their asses off" because the efforts to investigate and combat Moscow's meddling had only given the Russians what they wanted.

"If it was the GOAL of Russia to create discord, disruption and chaos within the U.S. then, with all of the Committee Hearings, Investigations and Party hatred, they have succeeded beyond their wildest dreams," Mr. Trump wrote.

The president's outburst ended a relatively subdued period after the deaths of 17 people in the shooting at a high school in Parkland, Fla., on Wednesday. He spent the following days praising law enforcement officials and emergency responders, and calling officials in Florida to receive updates. Mr. Trump met with two shooting victims in an unannounced visit to a Florida hospital on Friday evening, White House officials said.

As he shunned the golf course over the weekend (his predecessor had been criticized for golfing too soon after tragic events), he instead spent time mingling with his supporters, including Geraldo Rivera. Mr. Rivera said on Twitter on Sunday that he had seen firsthand that the president " was deeply affected" by the time he had spent with victims, "impressed by their courage" and "equally distressed by the savagery of their wounds."

But Mr. Trump also had time to stew over news coverage of the indictment against the Russians secured by Robert S. Mueller III, the special counsel leading an investigation into the Trump campaign's contacts with Russia. And he was surrounded in Florida by people who are likely to share his grievances: his two oldest sons, as well as John F. Kelly, his chief of staff, and Dan Scavino Jr., the White House social media director, who often emulates his boss's prose on Twitter.

The indictment says that while the Russians began their scheme in 2014 with the goal of undermining the American democratic system, they eventually shifted their focus to trying to help elect Mr. Trump and disparage his opponent, Hillary Clinton.

The president has repeatedly seized on the fact that the efforts started before he became a candidate, but he has glossed over the conclusion that they evolved toward supporting his candidacy.

The indictment does not assert any wrongdoing by the president or anyone affiliated with him, saying that some members of the Trump campaign were unwitting in their contacts with the Russian effort. It is also silent about whether the Russian campaign affected the election results.

Mr. Trump has long fought the idea that Moscow's efforts might have influenced the election, branding it as a "hoax" perpetrated by Democrats embarrassed about losing to him. He has made little if any public effort to rally the nation to confront the Russians for their intrusion.

The president's Twitter eruption began late Saturday night, when he accused the F.B.I. of having missed signals that could have prevented the school shooting because it was "spending too much time trying to prove Russian collusion with the Trump campaign."

He then lashed out at his national security adviser, Lt. Gen. H. R. McMaster, who had said at a security conference in Germany on Saturday that the indictment provided "incontrovertible" evidence that Russia had interfered in the American democratic system.

Mr. Trump said his adviser had "forgot to say that the results of the 2016 election were not impacted or changed by the Russians and that the only Collusion was between Russia and Crooked H, the DNC and the Dems." The nation's intelligence agencies believe that it is not possible to make such a calculation about the election outcome.

Then, on Sunday, Mr. Trump said that he had "never said Russia did not meddle in the election," quoting a comment he had made in a 2016 presidential debate.

"I said "it may be Russia, or China or another country or group, or it may be a 400 pound genius sitting in bed and playing with his computer," Mr. Trump wrote.. "The Russian "hoax" was that the Trump campaign colluded with Russia it never did!"

Yet he has repeatedly denied that Russia was behind any meddling, going so far in November as to suggest that he believed President Vladimir V. Putin's denials of interference over the conclusions of American intelligence agencies.

Mr. Trump also called Mr. Schiff, the California congressman, "Liddle Adam Schiff" and branded him "the leaking monster of no control," even as he praised him for his criticism of Mr. Obama's muted response to the Russian threat.

The president in the past has traded bitter Twitter messages with Mr. Schiff, accusing him of leaking classified information from the House Intelligence Committee's investigation into Russia's actions. Mr. Schiff shot back at Mr. Trump on Sunday, saying on Twitter that "if McMaster can stand up to Putin, why can't you?"

Initially, Mr. Trump had been swayed by advisers who described the indictment announced on Friday as a victory for him, since it identified particular bad actors outside the campaign and used the word "unwitting" to describe the contacts with the Trump campaign.

But as the weekend went on, Mr. Trump's longstanding frustrations with an inquiry that he has branded a "witch hunt" once again came to the fore. While the deputy attorney general, Rod J. Rosenstein, had noted repeatedly in announcing the indictment that it does not say that Russia changed the outcome of the election, Mr. Trump was angry because his own team had not gone further in his defense.

That included General McMaster, who, as an active duty military officer, takes the constrictions on what he can say politically very seriously. When he spoke in Germany, Mr. McMaster did not believe he could go further than the cold facts of the document, a reality that deeply frustrated the president, two administration officials said.

Although incensed by coverage of the Russia investigation, Mr. Trump spent part of the weekend focused on the school shooting. On Sunday, the White House announced that he would hold a "listening session" with high school students and teachers in Washington on Wednesday, and meet with state and local officials on school safety on Thursday.

Mr.. Trump also called three local officials, including Christine Hunschofsky, the mayor of Parkland. In an interview, Ms. Hunschofsky said she was struck by how affected the president had seemed by his hospital visit.

"He gave his condolences, and then he talked quite a bit," Ms. Hunschofsky said. "He said he had talked to somebody recovering in the hospital. I remember he kept saying, "How do you recover from that?"

nytimes