The state government has launched a crackdown on juvenile crime after the deaths of an Alexandra Hills couple and a woman in Townsville. The measures will target hardcore youth criminals who repeat offend. Courts will get more powers allowing them to require the fitting of electronic monitoring devices as a condition of bail for recidivist high risk offenders aged 16 and 17. The Youth Justice Act will be amended to include a reference to the community being protected from recidivist offenders. Courts will create a presumption against bail for youth offenders for committing further serious indictable offences like breaking and entering, serious sexual assault and armed robbery while on bail. Magistrates and judges will be able to seek assurances from parents and guardians that bail conditions will be complied with before an offender is released. The government will also enshrine in legislation the existing common law principle that offending while on bail is an aggravating circumstance when the court is imposing a sentence. The government will also move to further prevent crime by giving police metal detectors to target Gold Coast knife crime. Anti-hooning laws will be strengthened to hold the registered owner of a vehicle responsible except where the vehicle is stolen or the owner can identify another driver. A parliamentary inquiry also will examine the implementation of car engine immobilisers. Assistant Police Commissioner Cheryl Scanlon, Queensland's former Security and Counter Terrorism Command will lead a Youth Crime Taskforce to implement the new measures. Premier Annastacia Palaszczuk said the loss of four innocent lives linked to a spate of senseless crimes would not go unanswered. "It is clear to me and to the community that some young offenders simply don't care about consequences," she said. Ms Palaszczuk also announced that former Commissioner Bob Atkinson will report on the efficacy of the measures in six months. Police Minister Mark Ryan said young offenders needed to learn the consequences of their actions. "This is about targeting the hardcore repeat offenders, those 10 per cent of youth offenders who are frequently putting the community at risk. "We must stop young hardcore offenders being let out on bail and reoffending the next day. That is why we are making these changes to bail laws. "Ten per cent of all youth offenders account for 48 per cent of all youth crime. It is this group we will target with all the force and resources at our disposal." Ms Palaszczuk said the measures built on the government's plan announced in March last year, with $550 million in Youth Justice reforms already underway. Youth Justice Minister Leanne Linard said those reforms had led to a 23 per cent decrease in the numbers of youth offenders. "Our Transition 2 Success Program has a 67 per cent success rate," she said. "About 187 young people have attended and 67 per cent have not re-offended." The law changes will be introduced at this month's Parliament.