Manila's crime-fighting mayor Alfredo Lim, nicknamed 'Dirty Harry', praised police over the weekend for arresting his son, who was allegedly caught selling drugs. 'Congratulations to your men,' the mayor told Dionisio Santiago, head of the Philippine Drug Enforcement Agency, after undercover officers arrested 44-year-old businessman Manuel Santos Lim on Friday. Police allege that the younger Lim was caught trying to sell undercover agents 100 grams of methamphetamine, or shabu, worth an estimated 600,000 pesos (HK$114,000). Two others, Joel Sabado, 33, and Ronald Pascual, 38, were also arrested during the alleged drug deal at a dental clinic in Manila's Chinatown. The arrest took place as Alfredo Lim, a prominent member of the opposition ranks, was speaking at a protest rally against alleged corruption in President Gloria Macapagal-Arroyo's administration. In a nation where it has been the norm for government officials to shield relatives who run foul of the law, the mayor's response to the arrest is unusual - not least because he was informed about the operation against his son ahead of the arrests. A press release issued by the agency on Saturday quoted the mayor as telling agency operatives to 'just do your job' when they consulted him about the matter. Mr Santiago, expressed his gratitude to the mayor for giving his full co-operation. He also stressed that the operation was legitimate and 'without any political motive'. Mr Santiago was apparently referring to the fact that the agency operated under the Office of the President. Alfredo Lim, a former senator, is a staunch supporter of former president Corazon Aquino who has urged Mrs Arroyo to resign. The 78-year-old said that his son was 'old enough to face the consequences of his actions. Let him suffer for his actions'. The widower of Chinese descent added that he did not know whether his son was using drugs but 'what I do know is that he was having family troubles'. Manuel Santos Lim said on Saturday that he 'did not bother' phoning the mayor when he was arrested. 'I knew that he himself would arrest and charge me,' he said. Mr Santiago said the arrest and others like it had been made possible because Alfredo Lim had made Manila an 'open city' for his agents. He earned the nickname 'Dirty Harry' when he was a police general, having been suspected of tolerating extra judicial executions of criminals, especially drug suspects.