A German conservative politician who helped vigilantes arrest an agitated migrant may face expulsion from his party.

One week ago an Iraqi migrant who attempted to steal a bottle of wine in Arnsdorf, Germany was restrained by a group of vigilantes after they removed him from the shop.

The group of German men used cable ties to restrain the migrant, who was making threatening gestures, and tied him to a tree, handing him over to police shortly thereafter.

One of the men involved was Christian Democratic Union (CDU) local politician Detlef Oelsner. Now, his party – the party of German Chancellor Angela Merkel – is threatening to expel him unless he apologises for his actions, Die Welt reports.

Lars Werthmann, the chairman of the local association for the party, told German media: “We want an apology from him in public,” and warned: “If he does not apologise, we would seek to exclude him from the CDU local federation, because that use of force is simply out of the question for us.”

Mr. Oelsner was joined by three other men when he overpowered an angered Iraqi migrant who was attempting to steal a bottle of wine. The entire incident was caught on film as the 21-year-old Iraqi threatened the staff of the shop and harassed them before the group forcibly removed him from the premises.

Mr. Werthmann stated that the actions were excessive, and claimed that the four men involved had crossed the limit of what was acceptable in the situation. His comments echoed those of controversial violence researcher, Jörg Baberowski, who claimed that Germans should not fight back against migrants but rather leave confrontations exclusively to the police.

Police in the area are now saying that they are looking into claims that the migrant was falsely imprisoned by the group. The polcie had previously justified the actions of the vigilantes but may now be changing their policy.

Police Chief Conny Stiehl said: “The instinct to restrain the migrant was understandable, but it’s hard to say if it was necessary.” A police spokesman said that the authorities are examining whether or not to bring charges against the men and if their actions violated the laws pertaining to lawful arrest.

Joachim Renzikowski, a criminal law expert, claims that the actions of the vigilantes may not be covered under the “everyman arrest law” because the migrant had not yet stolen the bottle of wine but rather the vigilantes only suspected he would. He said that only when the suspect flees should then he be arrested.

Vigilante groups are growing across Europe as many are dismayed by the lack of police action toward migrant crime. In Germany, after the New Year’s Eve Cologne sex attacks, thousands of German men signed up to protect women from unwanted migrant sexual advances.