Piknik, a longtime Russian rock band, is now at the center of a tragedy.

Early Saturday, Piknik, one of Russia’s most popular heritage rock bands, published a message to its page on Vkontakte, one of the country’s largest social media sites: “We are deeply shocked by this terrible tragedy and mourn with you.”

The night before, the band was scheduled to play the first of two sold-out concerts, accompanied by a symphony orchestra, at Crocus City Hall in suburban Moscow. But before Piknik took the stage, four gunmen entered the vast venue, opened fire and murdered at least 133 people.

The victims appear to have included some of Piknik’s own team. On Saturday evening, another note appeared on the band’s Vkontakte page to say that the woman who ran the band’s merchandise stalls was missing.

“We are not ready to believe the worst,” the message said.

The attack at Crocus City Hall has brought renewed attention to Piknik, a band that has provided the soundtrack to the lives of many Russian rock fans for over four decades.

Ilya Kukulin, a cultural historian at Amherst College in Massachusetts, said in an interview that Piknik was one of the Soviet Union’s “monsters of rock,” with songs inspired by classic Western rock acts including David Bowie and a range of Russian styles.

Since releasing its debut album, 1982’s “Smoke,” Piknik — led by Edmund Shklyarsky, the band’s singer and guitarist — has grown in popularity despite its music being often gloomy with gothic lyrics. Kukulin attributed this partly to the group’s inventive stage shows.

After the collapse of the Soviet Union, Kukulin said, the band began performing with exciting light displays, special effects and other innovative touches. At one point in the 1990s, the band’s concerts included a “living cello” — a woman with an amplified string stretched across her. Shklyarsky would play a solo on the string.

This month, the band debuted a new song online — “Nothing, Fear Nothing” — with a video that showed the band performing live before huge screens featuring ever-changing animations.

Unlike some of their peers, Piknik was “never a political band,” Kukulin said, although that did not stop it from becoming entwined in politics. In the 1980s, Soviet authorities banned the group — along with many others — from using recording studios, while Soviet newspapers complained of the group’s lyrics, including a song called “Opium Smoke” that authorities saw as encouraging drug use.

In recent years, some of Russia’s most prominent rock stars have left their country, fed up with President Vladimir V. Putin’s curbs on freedom of expression, including regular crackdowns on concerts. Piknik had benefited from that exodus, Kukulin said, because the band had fewer competitors on Russia’s heritage rock circuit.

Unlike some musicians, Shklyarsky had not acted as a booster for Russia’s invasion of Ukraine, Kukulin said. Still, Ukrainian authorities have long banned Piknik from performing in the country because the group has played concerts in occupied Crimea. In a 2016 interview, Shklyarsky said he was not concerned about the ban.

“Politics comes and goes, but life remains,” he said.

Kukulin said that among Piknik’s songs was “To the Memory of Innocent Victims” — a track that could be interpreted as being about those who were politically oppressed under communism. Now, Kukulin said, many fans were hearing the song in a new way, as a tribute to those who lost their lives in Friday’s attack.