A general view of the cemetery where the Belgian mayor Alfred Gadenne was found dead in Mouscron, Belgium,?Sept 12, 2017. [Photo/Agencies]

A picture of the Belgian mayor Alfred Gadenne is displayed in the administrative center in Mouscron, Belgium, Sept 12, 2017. [Photo/Agencies]

MOUSCRON, Belgium - A Belgian teenager who blamed the local mayor for his father's suicide after he was fired from a town hall job has confessed to slashing the politician's throat in a cemetery on Monday night, public broadcaster RTBF said.

The murder of Alfred Gadenne, 71, the mayor of Mouscron and a former lawmaker in the regional parliament, has shocked the country, with the prime minister expressing his "horror".

The public prosecutor told Reuters that a man was under arrest after giving himself up to police at the scene after dark in Mouscron, an industrial border town of 57,000 close to the French city of Lille. He declined comment on media reports.

RTBF, citing sources including the suspect's lawyer, said he was 18 and told police he was avenging his father, who killed himself two years ago after losing his job as a local council employee. A box-cutter was found at the scene, where the young man had calmly called police to attend around 8 pm.

Gadenne, a conservative whose death prompted tributes from across the national political spectrum, acted as caretaker for the cemetery next to his home and was killed after going there to lock up for the night, as he did every evening.

Media reporting of this spare-time occupation during his decade as mayor had allowed the suspect to find Gadenne alone, RTBF said. It added that the man waited until he reached the age of majority so his mother, also a municipal employee, could not be held liable for his actions under Belgian law.

Mourners left flowers at the cemetery gates and visited the town hall to sign a book of condolence for the mayor.

Reuters