German prosecutors said Monday that they are not ruling out a political motive in the stabbing deaths of two Ukrainian soldiers in southern Germany on Saturday.

The two Ukrainians, who were 23 and 36 years old and undergoing medical rehabilitation in Germany, were killed at a shopping center in the village of Murnau in Upper Bavaria. Their names have not been released due to privacy laws.

Police arrested a 57-year-old Russian in his home on suspicion of murder shortly after the attack, police said.

The public prosecutor general’s office in Munich took over the investigation Monday because of a possible political motivation for the crime.

“The motive for the crime is currently unclear, although a political motivation cannot be ruled out and is being investigated in all directions,” said the prosecutor general’s office Monday.

Early indications suggested the three men knew each other, local police spokesperson Stefan Sonntag told dpa, the German press agency.

A spokesperson for the German government declined to comment on the case Monday, citing that the police investigation was ongoing. The Russian embassy has also declined to comment.

Mourners gathered near the scene of the attack with flowers and Ukrainian flags to hold a small vigil for the soldiers.

Two German-Russian nationals were arrested in Germany in a separate case this month on suspicion of plotting sabotage attacks, including on United States military facilities. Officials said their plot was an effort to undermine military support and aid for Ukraine.

More than 1 million Ukrainian refugees have come to Germany since Russia launched an invasion of Ukraine in 2022. Germany is also home to a significant Russian community, including 2.5 million Russians of German ancestry who moved to the country after the Soviet Union’s collapse in 1991.