Four Hungarian far-right extremists were sentenced to jail Tuesday over the killings of six members of the Roma minority, including a child, in a wave of racist attacks using guns, grenades and Molotov cocktails. A Budapest court sentenced Zsolt Peto and brothers Arpad and Istvan Kiss to life for the murderous spree between 2008 and 2009, while their driver Istvan Csontos received 13 years as an accomplice. The gang members, who hatched their plans in a pub in Debrecen in northeast Hungary, are hard-core football fans with neo-Nazi links. They showed no emotion as the verdicts were handed down. The gang killed six people and left another five seriously injured, all ethnic Roma, in a 14-month reign of terror that shocked Hungary. \"It is morally unacceptable, and in no country should it be permissible, that anyone should band together to commit crimes with the aim of ... intimidating an ethnic group,\" judge Laszlo Miszori said in his verdict. \"Nazi killers!\" shouted people who had gathered outside the court. Starting in July 2008, the Kiss brothers and Peto carried out nine brazen night-time assaults on Roma living in villages in northeastern and central Hungary. Csontos took part in the last two attacks as their driver. In one of the most gruesome attacks, a Roma father and his five-year-old son were gunned down as they tried to flee their house, which the gang had set on fire. In another incident, a woman was shot in her sleep. The gang\'s motive was to provoke a violent reaction from the Roma and spark inter-ethnic conflict, prosecutors said. The Hungarian police have been accused by victims\' relatives of being slow to investigate the killings, refusing for a long time to see any link or racial motive. After one attack, officers failed to cordon off the crime scene for 12 hours, attorneys for the victims\' relatives say. Three innocent young Roma also spent almost a year in custody on suspicion of involvement in another of the attacks. Attorney Laszlo Helmeczy told journalists Tuesday that the victims\' families planned to bring a civil case against the state, seeking compensation for \"mistakes\" by the police and intelligence services that delayed the suspects\' arrest. Police security was heavy inside and outside the court building for the verdict, which ends a two-and-a-half-year trial and comes a few days after the fourth anniversary of the last attack on August 2, 2009. All four accused, in custody since their arrests that month, admitted involvement in the attacks but pleaded not guilty to premeditated murder. Defence lawyer Zsolt Berdi said he intended to appeal the judgment. \"They wanted to start a civil war between Hungarians and Hungarian Roma. The charges should have been crimes against humanity, terrorism and racism,\" prominent Roma activist Aladar Horvath told AFP. About 100 people had gathered in front of the courthouse, including relatives of the victims, some wearing T-shirts bearing pictures of the victims. One T-shirt read: \"Their skin-colour was their crime\". Plagued by poverty and high unemployment and often shunned by the rest of society, Hungary\'s Roma -- who make up between five and eight percent of the 10-million population -- are often subjected to verbal and physical abuse. This has included harassment by far-right extremist groups and by the far-right Jobbik party, which vilifies them as criminals. Prime Minister Viktor Orban, a controversial figure who detractors say is eroding democracy in the EU member state, has been accused of presiding over a rise in anti-Roma feeling and anti-Semitism. In January, Zsolt Bayer, a prominent journalist close to Orban, equated Roma to \"animals\" who \"should not exist\". His newspaper was later fined by the country\'s media regulator. Zoltan Balog, minister for human resources, said Tuesday the case was a matter of \"human dignity\". \"No perpetrators of racist crimes can escape the law in Hungary,\" he said in a statement. Rights group Amnesty International meanwhile noted that: \"Today\'s verdict is a positive step, but Hungary has yet to learn the lessons from these killings.\" \"The authorities are still not doing enough to prevent and respond to violence against Roma,\" it said in a statement.