A Luxembourg court on Thursday imprisoned a 23-year-old Swedish man for plotting a terrorist attack on the 2020 Eurovision Song Contest in Rotterdam.

He was sentenced to eight years in prison, with six years suspended. The ruling caps a yearslong investigation that uncovered a sophisticated bomb-making operation and ties to international extremist networks.

The defendant, named as Alexander H., was found guilty of participating in a terrorist organization, as well as multiple violations of European firearms and explosives laws, local newspaper Luxemburger Wort reported.

Assistant Prosecutor David Lentz had sought a 12-year sentence in July, arguing that only the action by Luxembourg’s police and intelligence services helped prevent mass casualties.

The man was arrested in February 2020 after Luxembourgish authorities uncovered a professionally equipped bomb workshop in the basement of his father’s home in Strassen, central Luxembourg.

Investigators found TATP, nitroglycerine, a functional pipe bomb and a parcel bomb addressed to a Swedish film company. A French explosives expert told the court he had never seen a more advanced setup in a terrorism case.

According to the court, the defendant — then aged 18 — had spent months preparing attacks in Sweden and the Netherlands, including a planned mass-casualty assault on the 2020 Eurovision Song Contest, which was later canceled due to the Covid-19 pandemic.

Investigators discovered a Google document titled “Fun time for Eurovision 2020 — For a better and less over-accepting future,” co-authored with an alleged Dutch accomplice, outlining plans to poison attendees with cyanide or ricin, release chlorine gas, or disperse chemicals through ventilation systems or custom-built rockets, national TV channel RTL reported in July. Police later confirmed the seizure of chlorine-production materials and rocket prototypes.

The pair also explored ways to infiltrate security teams, block emergency exits and conduct secondary attacks, including a planned strike on an oil depot in Nacka, Sweden, for which the defendant had already mapped weak points in the site’s perimeter fence.

Dutch police questioned but did not arrest the alleged accomplice. The Public Prosecutor’s Office in Rotterdam said that the man did not actually intend to carry out an attack, Dutch outlet Het Parool reported Thursday.

According to authorities, the man’s plans were influenced by his involvement in extremist networks such as The Base, a neo-Nazi paramilitary group, Swedish outlet SVT reported in August.

The suspended portion of the man’s prison sentence is contingent on his completing a five-year deradicalization program and submitting progress reports to prosecutors every six months. Failure to comply would reinstate the full prison term.

The man and the prosecutor now have 40 days to appeal.