Three illegal immigrants were arrested in Tuen Mun yesterday following a police manhunt sparked by a failed robbery attempt on a hiker in a country park. Last night police were still interviewing the mainland trio to try to establish if they were involved in the attempted robbery. The 49-year-old hiker, surnamed Fung, was stopped by two men armed with pipes in Lam Tei, a popular hiking trail in the New Territories, shortly before noon. He struggled and managed to escape uninjured. The two robbers chased him for a short while but gave up the pursuit. When the hiker reached a safe place he phoned the emergency 999 number. Dozens of police and police dogs were immediately sent to search the area. About five hours later, two of the illegal immigrants, aged 24 and 29, were found near Lam Tei Reservoir. Knives, hammers and a telescope were seized from the pair, police said. Inside a hideout, a rubber boat and a pipe were also found. A third illegal immigrant was arrested in the park at 8pm. All three were arrested for immigration violations and detained at Tuen Mun police station, a police spokesman said. He added that they were still investigating whether the trio were involved in the failed robbery. There have been a number of robberies in country parks recently, including one on June 7, when a 64-year-old hiker, surnamed Ng, was robbed by a man armed with an axe while hiking along Hammer Hill Road, near King Lai Court, Wong Tai Sin. Following that incident, a concern group, Civilian Turn-up, proposed that location-tracking technology be used to help crime victims in country parks. The technology uses a special SIM card to link mobile phones to a tracking system. Location data would be sent via the mobile phone to an operator every 15 minutes. If no signal is received for more than one hour, the system generates a warning to the operator.