BERLIN (Reuters) - Germany’s Federal Supreme Court has issued an arrest warrant for a Tunisian man suspected of being the mastermind behind an attack on a Berlin Christmas market in 2016 that killed 12 people, a German newspaper reported on Thursday.

The Sueddeutsche Zeitung newspaper said German investigators had sought the arrest warrant for the 32-year-old man, identified only as Meher D., for suspected membership in Islamic State and as an accessory to murder.

No comment was immediately available from the court.

Anis Amri, a Tunisian man with Islamist militant ties, hijacked a truck and drove it into the crowded Berlin market in December 2016. He was shot dead by Italian police a few days later.

Security officials believe Meher D. left Tunisia in 2015 to join Islamic State in Libya and that he began communicating with Amri in the autumn of 2016 via a Whatsapp chat, the newspaper reported.

It cited a federal police document that said the suspect had played a significant role in motivating Amri to carry out the attack, the deadliest in Germany in decades.

It said it was unclear where the suspect was now living, but security officials believed he was still in Libya.

German investigators have been in touch about the case with Tunisian officials, who have been searching for Meher D. for some time. U.S. and German intelligence agencies were also aiding the investigation, the newspaper said.