Mike Mitchell, the musician best-known for his guitar solo on The Kingsmen's Louie Louie, has died aged 77.
A founding member of the band, he "peacefully passed away" on his birthday last Friday, drummer Dick Peterson confirmed to Rolling Stone.
"He was the kindest and most generous man on the planet," the band said in a statement on their official website.
"Mike was a favourite for his kindness, comedic nature as well as his musicianship," they added.
The Kingsmen were founded in Portland, Oregon in 1959, four years before they scored a global hit with their cover of Richard Berry's 1957 song Louie Louie.
Instantly recognisable from the intro, the song spent six weeks at number two in the US, and reached number 27 in the UK - thanks in part to the supposedly obscene lyrics that drew attention from the FBI.
The song was a staple of the band's raucous live shows, and was eventually recorded in Portland in 1963.
One story says the band went into the studio to cut a demo for a job on a cruise liner, another says they were invited to record it by local disc jockey Ken Chase, who thought The Kingsmen could score a "monster hit" with the song.
Either way, the band were unhappy with their performance, which was captured live on just three microphones for the sum of $36 (£26).
Singer Jack Ely, who was wearing dental braces, had to holler his vocals into a boom mike suspended from the ceiling while his bandmates played around him in a circle - making the lyrics (originally about a sailor trying to make his way home) all but incomprehensible.
But the song's raw energy propelled it up the charts, and brought it to the attention of some concerned citizens.
One of them, a father of a teenage girl who had brought the record home, wrote to Robert Kennedy, who was then the Attorney General, to complain about what he had heard.
"The lyrics are so filthy that I cannot enclose them in this letter," he wrote. "How can we stamp out this menace?"
His letter prompted an FBI investigation - and some of the potential lyrics included in their report are indeed eye-opening - but after several laboratory investigations, the song was declared "unintelligible at any speed" and cleared of being obscene.
In the meantime, however, the song had been banned in Indiana, and its notoriety resulted in even more sales.
"I always thought the controversy was record company hype," Ely, who died in 2015, told Rolling Stone.
Peterson added: "When Louie Louie was banned in Indiana back in 1964 by then-Governor Walsh, every kid had to have a copy, and the record took off like wildfire across the country."
Mitchell's contribution was the song's eccentric guitar solo, which influenced a new generation of rock-and-rollers.
"I learned to play the guitar because of Mike Mitchell," said The Eagles' Joe Walsh, upon learning of his death. "I know every one of his solos, mistakes and all. We're losing the good guys."
The Oregon Music Hall of Fame also saluted the guitarist on Facebook, noting, "He never let his chops fall behind. His playing just got better as he aged."
The Kingsmen never truly capitalised on the success of their runaway hit, falling victim to in-band fighting. In fact, Ely and bassist Bob Nordby had actually quit before Louie Louie was released.
However, Mitchell continued to record with a new line-up, scoring some minor US hits in the 1960s, including a cover of Money (That's What I Want) and the novelty song Jolly Green Giant.
The band quietly came to an end in 1968, but reformed in the late 70s after the movie Animal House re-introduced Louie Louie to a new generation; and they continued to tour into the 2010s.
In the meantime, Louie Louie has been covered more than 1,000 times - second only to The Beatles' Yesterday. Sadly, the original writer, Richard Berry, initially failed to capitalise on the success, having sold the publishing rights in 1957 to pay for his wedding.
He eventually regained some control of the music in 1986, and sold his share for a substantial sum in 1992.
The Kingsmen's recording was honoured by the Rock and Roll Hall of Fame and the Grammy Hall of Fame, while Rolling Stone magazine placed it 55th in its list of the 500 Greatest Songs of All Time.
Reflecting on his career in a 1999 radio interview, Mitchell said he wasn't bothered that The Kingsmen were defined by the song.
"We're just happy to have any success, that we can still do this," he said. "It's actually a wonderful career that we've had."
The musician is survived by his children Samantha and Max.