Germany is now targeting Facebook CEO Mark Zuckerberg, and other company executives, as part of an investigation into hate speech on the platform.

The preliminary inquiry by the Munich prosecutor’s office is the result of a lawsuit filed by German attorney Chan-jo Jun regarding hateful Facebook posts. The complaint specifically names Zuckerberg, Facebook COO Sheryl Sandberg, and other European execs, reports Der Spiegel.

Jun has reportedly listed 438 Facebook postings that include threats of violence, Holocaust denial, and references to Nazi-era genocide. The lawsuit alleges Facebook did not delete the specified posts over the past year despite the fact they were flagged as inappropriate.

A similar complaint brought against the company by Jun was rejected on the grounds that Facebook was not liable under German law, as its European operations are based outside the country in Ireland.

Facebook claims it has not broken German law, which prohibits the publication of such categories of speech, and is actively patrolling and deleting hate speech from its platform.

“We are not commenting on the status of a possible investigation but we can say that the allegations lack merit and there has been no violation of German law by Facebook or its employees,” said a Facebook spokesperson in a statement. “There is no place for hate on Facebook. We work closely with partners to fight hate speech and foster counter speech.”

Facebook, under its own regulations, defines hate speech as: “Content that attacks people based on their actual or perceived race, ethnicity, national origin, religion, sex, gender, sexual orientation, disability or disease.” It claims it removes content, disables accounts and works with law enforcement when it believes the material in question poses “a genuine risk of physical harm or direct threats to public safety.”

In the face of mounting public pressure, Facebook hired a German firm to quickly delete hate speech at the start of the year. In May, the company (alongside a number of other tech giants, including Twitter and YouTube) agreed to new EU rules that demanded online hate speech be removed within 24 hours.

Germany’s strict laws regarding incitement to hatred have in the past been applied to cases regarding anti-Semitism and Holocaust denial. The country has been trying to crack down on what it alleges is a rise in hate speech online resulting from the refugee crisis in Europe.