The death of a German politician and ally of Chancellor Angela Merkel who was found dead in his garden was allegedly the work of an assassin who disagreed with his immigration policy.

"According to what we know, we must now assume that the perpetrator is a right-wing extremist and that the crime has a right-wing extremist backdrop," said German Interior Minister Horst Seehoffer.  

Walter Lubcke was district president of the regional council of the central city of Kassel, and a member of Ms. Merkel's governing center-right Christian Democratic Union (CDU), which described him as a "bridge builder" who never shied away from "telling it as it is".  He was a supporter of Merkel's open-door policy for refugees.

Lubcke was found dead earlier this month in the garden of his home of a gunshot wound to the head.  There was no indication of suicide and he appears to have been shot execution-style.  

The suspect has been identified as a 45-year old man; German media calls him "Stephan E.".  He has had constant run-ins with the law throughout his adult life, including a bomb attack on a refugee home in 1995 for which he received 6 years in prison.  Public television reported that he is active in extreme-right and neo-nazi groups.  The German daily Suddeutsche Zeitung reported the suspect had issued several death threats in social media.

"A right-wing extremist attack on a leading representative of the state is an alarm bell and is directed against us all," said Seehofer.  "Right-wing extremism is a considerable and serious problem to our free society."