MOSCOW—For decades, Russia suffered from terrorist attacks on public places. An Islamist underground blew up Russian metro stations and airports, took thousands of hostages, and killed people with bombs on the streets.

But in all these years, Russia has never had a teenage student shooting at dozens of innocent people.

That changed Wednesday with an attack on a college in Kerch, a town on the Crimean Peninsula—Ukraine’s territory that Russia annexed in 2014.

Russian state-controlled media reports say 18-year-old student Vladislav Roslyakov, who is alleged to have had a strong interest in serial killers and a professed dream to become famous as the gunman of a Russian version of Columbine, killed at least 19 and wounded 47 people with a rifle at the campus.

In the images captured by school security cameras, a slim Roslyakov is shown wearing a white T-shirt and dark pants—a likeness that resembles the chilling form of Columbine gunman Eric Harris that later emerged in surveillance photos from the day of that massacre.

The April 1999 Colorado school shooting ended with 15 students killed by two student gunmen.

The reports also said Roslyakov had an official permit to use the weapon, which he obtained earlier this month. To get a gun permit, Russian citizens are obliged to get examined by a psychiatrist. It is unclear, however, if Roslyakov had passed the test.

At about 12:15 p.m. Wednesday, students at Polytechnical College had come out of their classrooms for a long break when they heard an explosion. A device, reported to be stuffed with pieces of metal, blew up in a crowded canteen. One of the surviving witnesses, Anastasia, told Radio Echo of Moscow: “I saw orange flashing light in the canteen. When I opened my eyes, there was blood everywhere,” she said. “Somebody had a missing leg, another person’s scalp was broken.”

Pro-Kremlin Russia Today media group quoted one more victim in its Telegram messenger feed, saying that the college was attacked by several gunmen: “They shot at students and teachers, at everybody on their way and threw explosives around,” the victim said.

Sergei Aksyonov, the pro-Moscow leader of Crimea, confirmed that Roslyakov was the only attacker at the college. However, a separate Russian news agency, RBK, interviewed a witness who said that there were several gunmen, not just one—a discrepancy that U.S. mass-shooting investigators have also sometimes confronted.

At first, Russian security service officials qualified the attack on the college as “terrorism,” but then changed the status to “murder.” A Russian Investigative Committee official statement said that Roslyakov had committed suicide, that his body was found in the college’s library—the same campus location where the Columbine killers’ bodies were located by police.

In Moscow, experts had many questions for investigators.

“ There are so many corpses there. This was a real terror attack. Someone was running and throwing explosive devices, bombing everywhere. ” — Olga Grebennikova, principal

“It all sounds very strange: The guy could not shoot so many people from a pump rifle alone, as he would have to reload it several times,” independent military adviser Alexander Golts told The Daily Beast.

The college’s principal, Olga Grebennikova, insisted that the attack in Kerch was an act of terrorism. “There are so many corpses there. This was a real terror attack. Someone was running and throwing explosive devices, bombing everywhere,” she told Kerch.net Internet news agency.

Initial reports said that Roslyakov's nickname in the Russian Vkontakte social network was Reich, but a report by the independent Meduza news service debunked those claims.

President Vladimir Putin issued a short statement, promising to check all versions of events and motives behind the attack. Russian senator Alexey Pushkov blamed aggressive foreign action movies: “These movies create a wrong stereotype. We should fight against films that demonstrate psychopathic men preparing for this kind of murders.”

Armored vehicles and security-service soldiers surrounded the college and Roslyakov’s house in Kerch, a city with about 146,000 people near the controversial new bridge connecting Crimea to Russia. Investigators summoned Roslyakov’s parents for questioning. By 7 p.m. security services removed a second explosive device from the college.

In both Russia and Ukraine, people mourned the victims.

The college did not have any security posted, leaving the door open for anybody to walk in with a machine gun or a bomb. But the school’s website does have an “anti-terrorism” page, which lists steps for students and staff to follow for their own security.

Moscow city hall’s principal deputy, Ilya Yashin, was wondering how one student could prepare such a massive attack alone.

“Our propaganda tells us that Crimea is safe for tourists and here we have some teen, allegedly angry with his teachers, who kills 19 people and wounds almost 50 more,” Yashin told The Daily Beast. “Even if the investigation shows that it was just one mentally sick kid, this is still a horrible shame for Russian security services!”

An earlier version of this story incorrectly identified the shooter's social media pseudonym as Vladislav Reich.