Bob Dylan often has things to say in dark times. He threw another surprise late Thursday night in these uncertain days of COVID-19. On Twitter, Dylan dropped a new (old) song, "Murder Most Foul."

It's the longest song he's ever recorded – 16 minutes, 56 seconds (25 seconds longer than 1997's epic "Highlands," for you Dylanologists).

"It was a dark day in Dallas," Dylan starts on "Murder Most Foul." "November '63. A day that will live on in infamy."

Yes, it's the story of the assassination of President John Kennedy and the death of the dream and the ideals that he stood for.

Backed by impressionistic piano and violin shading, Dylan turns the song into a rambling series of rhyming couplets filled with all kinds of pop culture references.

"The Beatles are coming/ they're gonna hold your hand," he sings with his familiar parched voice.

Before it's over, Dylan references many musical greats from John Lee Hooker and Charlie Parker to Patsy Cline and Nat King Cole. More modern stars get mentioned, too, like Don Henley and Glenn Frey and "Lindsey [Buckingham] and Stevie Nicks."

Weaved throughout are references to the JFK situation, whether it's VP Lyndon Johnson being sworn in on Air Force One or "That strip club owner named Jack," referring to Jack Ruby who killed alleged JFK assassin Lee Harvey Oswald. Dylan mentions Dealey Plaza and the Crossroads in juxtaposed couplets. And Marilyn Monroe is there, too.

The bard does deliver one positively Dylanesque line: "I hate to tell ya mister but only dead men are free."

It's unclear exactly when Dylan -- who hasn't offered any new original tunes since 2012's "Tempest" album -- recorded "Murder Most Foul." Judging by his vocal vibe and the spare jazzy instrumental accompaniment, the recording sounds of recent vintage.

Dylan made a brief statement on Twitter:

Greetings to my fans and followers with gratitude for all your support and loyalty over the years.

This is an unreleased song we recorded a while back that you might find interesting.

Stay safe, stay observant and may God be with you.

Bob Dylan