A German neo-Nazi was sentenced on Thursday to life in prison for murdering pro-migration politician Walter Luebcke, a killing that shocked the country and highlighted the growing threat of right-wing extremism.

Stephan Ernst, 47, was found guilty of shooting dead the lawmaker from Angela Merkel's conservative CDU party on June 1, 2019, in what is believed to be Germany's first far-right political assassination since World War II.

Luebcke was found on the terrace of his home near the central city of Kassel, with an autopsy showing he was shot in the head at close range.

Handing down the verdict, judge Thomas Sagebiel said there was "no room for manoeuvre in the murder conviction ... and in the assessment of culpability".

Addressing Luebcke's family, he added: "We know that we can hardly measure your loss and that the proceedings were very painful for you. Our task was to conduct a fair trial and... we have endeavoured to do that."

A co-defendant, Markus Hartmann, was cleared of being an accessory in the killing but found guilty on weapons possession charges and received a suspended sentence of 1.5 years.

Summing up its case in December, the prosecution said Ernst had been motivated by "racism and xenophobia".

Walter Luebcke was shot dead on June 1, 2019, in what is believed to be Germany's first far-right political assassination since World War II
Walter Luebcke was shot dead on June 1, 2019, in what is believed to be Germany's first far-right political assassination since World War II POOL / Swen Pförtner

Luebcke, 65, headed the Kassel regional council in the state of Hesse. He supported Merkel's 2015 decision to open the country's borders to refugees and spoke in favour of hosting asylum seekers in a local town.

Prosecutors said Ernst had attended a speech by Luebcke in October 2015 when the politician defended helping refugees, adding that anyone who did not agree with those values was "free to leave the country".

The remark was widely shared online and turned Luebcke into a hate figure for the far right.

After the speech, Ernst "increasingly projected his hatred of foreigners" on to Luebcke, prosecutors said at the opening of the trial in June.

Following mass sexual assaults by migrants against women in Cologne on New Year's Eve 2015 and a 2016 Islamist attack in the French city of Nice, Ernst allegedly began tracking Luebcke's movements.

Between 2016 and 2018, prosecutors said he worked with Hartmann to improve his skill with firearms.

Prosecutors are calling for Stephan Ernst, 46, to be given a life sentence for the murder of Luebcke
Prosecutors are calling for Stephan Ernst, 46, to be given a life sentence for the murder of Luebcke POOL / Boris Roessler

In the course of their investigations, prosecutors separately charged Ernst with attempted murder for allegedly stabbing an Iraqi asylum seeker in the back in 2016.

They also uncovered weapons and ammunition belonging to Ernst, including revolvers, pistols and a submachine gun.

Although Ernst initially admitted killing Luebcke, he later retracted his confession and said Hartmann had pulled the trigger.

But he then sacked his defence lawyer and reverted to his original confession, claiming he had been pushed into blaming Hartmann.

Ernst has a long criminal history and was known to police as a neo-Nazi sympathiser.

He was convicted of an attempted bomb attack on an asylum home in 1993. German media say he took part in neo-Nazi clashes targeting a union demonstration in 2009.

But Ernst then slipped off the security services' radar, fuelling criticism that the authorities were not taking the far-right threat seriously enough.

German police came under fire years earlier for overlooking racist crimes after it emerged that a neo-Nazi terror cell, the National Socialist Underground, had killed 10 people, mainly immigrants, between 2000 and 2007.

In October 2019, just months after Luebcke's death, Germany was rocked by a shooting at a synagogue in the eastern city of Halle that left two people dead.

Neo-Nazi Stephan Balliet, 28, was sentenced to life in prison in December for that attack, described as the country's worst anti-Semitic atrocity since World War II.

Last February, another gunman shot dead nine people of migrant origin in the central town of Hanau.

Interior Minister Horst Seehofer has declared far-right extremism the "biggest security threat facing Germany".

He has promised tougher security measures, including a crackdown on online hate speech.