Stefan Alois Lee, 47, and a group of at least eight other motorcyclists had pulled to the side of Interstate 15 to put on rain clothing at about 5:15 p.m. PDT Tuesday, the Nevada Highway Patrol said.

The semitrailer, driven by Edwin Zuk, 27, of Illinois, swerved and the trailer slammed into a parked Harley-Davidson motorcycle that hit Lee.

“It was just a freak accident,” Trooper Joseph Fackrell said.

Lee was pronounced dead at the scene, about 63 miles north of Las Vegas and 10 miles south of the Nevada-Arizona border town Mesquite, Fackrell said.

Lee was the frontman for Gotthard, one of Switzerland’s most successful bands, selling millions of albums.

Lee was among 21 tourists including Gotthard bassist Marc Lynn and Lee’s girlfriend, Brigitte Voss-Balzarini, who arrived in the United States during the weekend, said Jan Bayati of German music management company Bottom Row. No one else was injured in the crash.

“Lee wasn’t just one of the best voices in rock, he also had an extraordinary personality,” Bayati said.

The Clark County coroner listed Lee’s hometown as Porza, Switzerland.

Fackrell said the investigation was continuing, but drugs, alcohol and speed did not appear to be factors in the crash.

Click here for Gotthard’s website.