A German federal court has rejected an appeal by a far-right extremist sentenced to 14 years in prison for the attempted murder of a politician who is now Cologne's mayor.

The defendant, identified only as Frank S. in line with German privacy rules, was convicted by a Duesseldorf court in July.

Henriette Reker, who was in charge of housing refugees in Cologne at the time, was stabbed in the neck Oct. 17, 2015 as she campaigned. Reker was elected mayor the following day while in an induced coma and took office about a month later.

Judges in Duesseldorf found that the assailant, a German in his mid-40s, wanted to "send a signal against the government's refugee policy."

The Federal Court of Justice said Monday that it has rejected his appeal.