German police have made two more arrests related to the killing of a pro-migrant politician, allegedly by a far-right sympathiser, federal prosecutors said Thursday.
"We confirm two arrests," a spokeswoman for the Federal Prosecutor's Office told AFP.
Elmar J., 64, was detained for selling in 2016 the weapon allegedly used by key murder suspect Stephan Ernst, who has confessed to the crime.
The second man, Markus H., 43, is held on suspicion that he set up the contact between the gun-seller and Ernst.
Both are German citizens and are under investigation for aiding and abetting murder.
On Wednesday, Germany's interior minister Horst Seehofer said Ernst had "confessed" to the killing of local politician Walter Luebcke and had said that he "acted alone".
Luebcke was an outspoken defender of Merkel's decision to welcome refugees and in 2015 drew the wrath of right-wing extremists by telling Germans who objected that they could leave the country.
He was found dead on the terrace of his family home in Wolfhagen near Kassel, having been shot in the head at close range on June 2.
The killing has deeply shaken Germany, and raised questions about whether the country has failed to take seriously a rising threat from neo-Nazis.
According to reports by media outlets NDR, WDR and Sueddeutsche Zeitung, Ernst confessed to having several weapons and gave details to police of how they were obtained and where he hid them.
Investigators reportedly found five weapons, including the one allegedly used in the murder, buried on his employer's premises.
Police are investigating whether the newly-arrested men have any connections to the right-wing extremist scene.
Their apartments were searched in Kassel and Hoexter on Wednesday night and objects related to Germany's Nazi era were reportedly confiscated.