BERLIN (AP) — Hubert Aiwanger, the leader of a conservative party that has become a mainstay of Bavarian politics and sought to expand its influence across Germany, has been found dead at a Berlin hotel.

The body of Aiwanger, who was Bavaria's deputy governor and the southern state's economy minister, was found in his hotel room in the center of the capital on Wednesday evening, Berlin police and prosecutors said. Prosecutors said that an autopsy carried out Thursday produced no evidence that anyone else was involved in his death.

German news agency dpa reported that the 55-year-old Aiwanger had planned to make a speech on Wednesday afternoon at the opening of a Berlin office of his party, the Free Voters, but pulled out of the event for health reasons.

Aiwanger had been the party's leader in Bavaria since 2006 and its national leader since 2010.

The combative politician with a strong regional accent and a populist touch made his party a serious rival to Bavaria's long-dominant Christian Social Union, or CSU, which is part of the center-right bloc that currently leads Germany.

On his watch, Free Voters entered the state legislature in Munich in 2008. A decade later, when the CSU lost its majority in the state legislature, it entered Bavaria's government as the junior coalition partner.

Shortly before Bavaria's 2023 election, Aiwanger faced a furor that started with allegations — denied by the politician — that he was responsible for an antisemitic flyer when he was a high school student 35 years earlier. Free Voters emerged unscathed from the election, gained support and remained part of the state government.

Aiwanger's party has made only limited inroads outside Bavaria and he wasn't able to lead it into the national parliament.

Bavarian governor Markus Söder wrote on X that “the sudden death of Hubert Aiwanger is an absolute tragedy.”

Aiwanger is survived by his partner, Free Voters politician Tanja Schweiger, and two children.