WASHINGTON — President Trump told a gathering of police chiefs in Chicago that his predecessors should have killed the murderous Islamic State leader Abu Bakr al-Baghdadi, who blew himself up during an American raid on his compound in Syria on Saturday.
“He should have been killed years ago, another president should have gotten him,” Mr. Trump said of the ISIS chief.
A day after he formally announced the most high-profile American counterterrorism action since the 2011 killing of the Qaeda leader Osama bin Laden, Mr. Trump continued to revel in its success, and reprised his blunt language from a day earlier.
“He was a sick and depraved man and now he’s dead — he’s dead as a doornail,” Trump said of Mr. al-Baghdadi, drawing some laughter from his audience. “And he didn’t die bravely, I can tell you that.”
In a typically freewheeling speech to the annual conference of the International Association of Chiefs of Police that lasted more than an hour, Mr. Trump struck a stern law-and-order tone as he lashed out at the city’s police chief, condemned local gun violence, railed against illegal immigrants, and denounced an apparently staged assault on the actor Jussie Smollett.
Mr. Trump said that Mr. Smollett, who made a questionable claim last year that he was assaulted in Chicago by Trump supporters in red “Make America Great Again” hats, “beat himself up.” (Mr. Smollett was charged with filing a false police report before the charges against him were dropped as part of a deal with prosecutors.)
Mr. Trump drew an unlikely line between Mr. Smollett’s alleged hoax and the House Democratic inquiry now underway against him back in Washington.
“It’s a scam, just like the impeachment of your president is a scam,” Mr. Trump said.
Mr. Trump did not explain how exactly his predecessors had failed in their pursuit of Mr. al-Baghdadi. The ISIS leader was imprisoned by American forces in Iraq in 2004, during the administration of George W. Bush, but was seen as an insignificant figure at the time. He was released after less than a year and then dropped out of view for several years. United States officials did not appreciate his import as an insurgent leader until 2009, early in the administration of President Barack Obama.
Mr. al-Baghdadi became a top target of American forces deployed by Mr. Obama to Iraq and Syria after he led ISIS’s seizure of large swaths of territory in those countries in 2014. And United States officials say that Mr. Trump’s abrupt withdrawal of American troops from northeastern Syria earlier this month had complicated planning already underway for the treacherous raid on Mr. al-Baghdadi.
But his critique echoes that of the mother of Kayla Mueller, a young American aid worker who was abducted in Syria in 2013 and enslaved and raped by Mr. al-Baghdadi. She was killed under murky circumstances in February 2015.
“I still say Kayla should be here, and if Obama had been as decisive as President Trump, maybe she would have been,” Ms. Mueller’s mother, Marsha Mueller, told The Arizona Republic on Sunday.
Mr. Trump also reprised past criticisms of Chicago’s Democratic political establishment, pointing to the city’s long-running epidemic of gun violence.
“All over the world they’re talking about Chicago,” Mr. Trump said. “Afghanistan is a safe place by comparison.”
Mr. Trump noted that Chicago’s police superintendent, Eddie T. Johnson, was not in attendance. Last week, Mr. Johnson released a statement saying that he could not “in good conscience stand by while racial insults and hatred are cast from the Oval Office or Chicago is held hostage because of our views on new Americans.”
Mr. Trump repeatedly insulted Mr. Johnson by name, in some cases drawing applause. “He’s not doing his job,” Mr. Trump said, citing the city’s homicide rate.
Writing on Twitter shortly after Mr. Trump spoke, Chicago’s mayor, Lori E. Lightfoot, denounced his “insulting, ignorant buffoonery.”
“Rather than belittle Chicago’s communities with hateful and dishonest rhetoric, he needs to go back to D.C. and face his fate,” Ms. Lightfoot wrote, adding that she stood by Mr. Johnson.
Mr. Trump was introduced at the event by the president of the police chiefs group, Paul Cell, who called him “the strongest supporter of law enforcement that this profession has ever seen.”
After his remarks, Mr. Trump headed to a round table with supporters and a private fund-raising lunch at the Trump International Hotel and Tower in downtown Chicago. He was scheduled to return to Washington in the afternoon for a Halloween event on the South Lawn of the White House.