US parents are being urged to check where potential paedophiles live before Halloween

People in Kentucky, Indiana and Ohio can see where registered sex offenders are before sending their children trick-or-treating

Parents have been urged to check the register before they take their children trick-or-treating (Rex)

Parents in the US have been urged to use online tools to check for registered sex offenders in their area before Halloween.

People in Kentucky, Indiana and Ohio can look up a written list of thousands of sex offenders by street name to see if there are any homes they would want their children to avoid while trick or treating.

The updated lists are available on the state governments' websites, Lex18.com reported.

Under federal law, sex offenders in the US have to update their address in the registry within three days of moving to a new home and inform local police about their whereabouts.

It is up to each state how much information they release to the public and some states only list the details of the most violent offenders.

The act is known as Megan’s Law after seven-year-old Megan Kanka from New Jersey who was raped and murdered by her next-door neighbour Jessie Timmendequas.

Timmendequas had previous convictions for child sexual assault.

A similar law – dubbed Sarah’s Law after murdered schoolgirl Sarah Payne – was introduced in the UK in 2010.

UK parents have the right to check with police if anyone with regular unsupervised access to their children has a previous conviction for child sex offences.

But the US law’s effectiveness has been called into question since it was passed in 1996.

Critics say it has lead to vigilante killings, such as the murder of William Elliott and Joseph Gray, who were shot both shot to death in their homes in 2002 by Stephen Marshall – a man who reportedly went onto the register to find people to kill.

Others have said it does not stop the number of child sex assault cases as the majority of cases involve someone who is known to the child such as a family member or friend.