Three people on a motorbike tried to snatch a woman's chain here but couldn't do so as she raised an alarm, following which one of them, a juvenile, was arrested, police said on Thursday.The incident happened around 11 p.m. on Wednesday near Nathu Colony Chowk in east Delhi's Mansarovar Park area.Arpana, 32, was heading towards her house in Ram Nagar from Nathu Colony with her husband when the three assailants riding on a motorbike threatened the woman with a firearm and tried to grab her chain.When the woman raised an alarm, the accused got scared and tried to flee on their bike which skid. They fell on the ground. Two of them managed to run away, but the juvenile was nabbed by the passersby."We have apprehended a juvenile and impounded the bike on which they were trying to flee after committing a snatching bid," a police official said."The two other snatchers have been identified and they would be arrested soon," the official added.