A German court found a former Syrian intelligence officer guilty of crimes against humanity and sentenced him to life in prison — a first after a decade of war.

When detainees arrived at the security office in Syria, it “welcomed” them with an hour of whipping or beating, they told a German court.

In the world’s first trial prosecuting state-sponsored torture in Syria, the German court, in Koblenz, on Thursday convicted the former intelligence official in charge of that security office, the notorious al-Khatib unit in Damascus, of crimes against humanity and sentenced him to life in prison.

Human rights lawyers and Syrian survivors hailed the verdict as a landmark in the international quest to hold accountable those who committed war crimes during nearly 11 years of war in Syria.

It also set a precedent reaching far beyond Syria: It was the first to target atrocities by a government that is still in power, said Stefanie Bock, the director of the International Research and Documentation Center for War Crimes Trials at the University of Marburg in Germany.

Raslan, who served as a colonel in a Syrian intelligence service, was ultimately just a cog in the extensive machinery of repression in Syria.

Raslan — accused not only of committing more extensive crimes, but of crafting policies that resulted in mass civilian deaths — are still living freely in Syria, including its autocratic president, Bashar al-Assad.

al-Assad, and jihadists from Al Qaeda and the Islamic State who took advantage of the conflict’s chaos, also committed war crimes.

One reason, experts say, is that unlike leading Nazis after World War II or Rwandan officials who were convicted of the atrocities they committed, the Syrian government, whose military and security services are responsible for the bulk of the violence in the country, remains in power, preventing the apprehension of its leaders and officers.

As a result, victims of the Syrian government and human rights lawyers have focused their efforts in countries that accept “universal jurisdiction,” a principle stipulating that in the case of crimes against humanity and genocide, normal territorial restraints on prosecution do not apply.

It has also become home to hundreds of thousands of Syrian refugees, putting it at the center of efforts to prosecute Syrian officials.

A Syrian doctor accused of torturing detainees in a secret military prison and killing at least one of them will soon stand trial in Germany on charges of crimes against humanity and causing grievous bodily harm.

Human rights lawyers concede that so far, the cases have targeted low- and middle-ranking Syrian officials or soldiers.

But lower-level prosecutions could facilitate future prosecutions of more senior officials by introducing documents, witness statements and knowledge about the Syrian state’s operations into the court record, Mr.

“If you don’t start now, then in 10 years, you cannot get al-Assad or his chief of intelligence because you have no evidence,” Mr.

Raslan’s conviction would draw attention to the many more crimes committed during the Syrian war that have not been prosecuted, and to the officials who committed them but are still free