Hong Kong's top prosecutor says his decision to send letters to 109 protesters who escaped criminal charges over a rowdy anti-budget protest earlier this year was an 'appropriate' move to remind demonstrators to be peaceful and considerate of others. The letters were sent on Friday, after four of 113 people arrested on March 6 in Central - League of Social Democrats chairman Andrew To Kwan-hang, league member Raphael Wong Ho-ming and activists Ip Ho-yee and Bobo Yip Po-lam - were charged with assisting or taking part in unauthorised assembly. They are due to appear in court on Thursday. Quoting from the public order ordinance, the two-page missive reminds recipients that the offence of unauthorised assembly could mean five years in jail. Director of Public Prosecutions Kevin Zervos SC said that while letters of this kind were routinely sent to people in cases where a prosecution was not made, a mail-out on this scale had not been done before. 'I think there's an obligation on a modern-day prosecutor to explain his reasons, and in this instance, I decided not to prosecute taking everything into account,' he said. 'But at the same time, I wanted them to know that it was only in relation to this event and to make a point about the way they conducted themselves on the day.' Zervos said the letter was 'appropriate' and a 'means by which you could deal with it without the necessity of bringing them before a court'. He said if he had not sent a letter, he would not have been fulfilling his responsibilities. 'It's notifying a person of the fact that whilst they are not being prosecuted, their conduct in question was inappropriate and reminding them of their fundamental responsibilities as a citizen.' In the letter, Zervos writes that the protesters' conduct had 'caused serious civil disturbance and disruption which showed a lack of regard and concern for others'. 'By your actions, you blocked a major carriageway and disregarded repeated requests by the police to disperse. You were notified by the police that you were participating in an authorised assembly and breaching the law. It resulted in serious inconvenience to other road users with the potential of creating a danger or hazard to public safety as well as employing a large number of police officers to regulate and control the situation,' the letter states. Zervos said the letter was also important because he had noticed a recent trend of more violent protests. 'It's important, at this juncture, given the fact that there have been an increasing number of demonstrations [with an] increasing number of acts of aggression and violence, and I think people need to be reminded that the right to demonstrate is the right to peaceful demonstration. 'When they are exercising their right, they should always bear in mind and show concern for others as well ... We're living in a time where rights and freedoms are important but, equally, law and order is important. It's letting people know that they must respect the law and others. It's not about the individual; it's about the community good.'