The news ricocheted around the web immediately early Monday afternoon: CBS News was reporting that Tom Petty was dead.

It kicked off widespread reaction and remembrances, with star singers like John Mayer, Shania Twain and Jon Bon Jovi all paying tribute to Mr. Petty on Twitter.

It soon emerged, however, that the news was premature. It was not until just before midnight that Mr. Petty’s manager announced that he had died about 11:30 p.m.

When CBS reported Mr. Petty’s death on Twitter, preceded by a capitalized banner “JUST IN,” the network attributed the news to the Los Angeles Police Department. In an article published online, there was no mention of the L.A.P.D., merely the phrase “CBS News has confirmed.” (CBS later deleted the tweet.)