LYNN – A bomb scare rattled city residents Monday afternoon when what was thought to be a suspicious device was found underneath a tree at Red Rock Park.A crowd of onlookers anxiously gathered at the scene on Lynn Shore Drive as the State Police Bomb Squad and a robot checked out the suspicious item, which was determined to be a harmless backpack filled with personal items and alcohol.A few minutes after the backpack was removed, an unidentified 53-year-old Plymouth man, who authorities say was intoxicated, attempted to claim it and was taken into protective custody.”It (bag) was rendered safe and was not a bomb,” said Lynn Deputy Fire Chief James McDonald. “I don’t think the general public has anything to be nervous about and there is no need to be alarmed.”Despite the false alarm, residents of Lynn and Swampscott remain on edge following three previous incidents involving pipe bombs.The first happened last Monday on Hillside Avenue in Swampscott, when a resident found a pipe bomb in the street. It was described as two propane tanks held together by duct tape with a small pipe attached to it and was detonated by the State Police Bomb Squad.The second, found on Essex Street, exploded and blew out the windows in a vehicle Wednesday. The third incident happened Saturday night, where a Collins Street man found an intricately assembled pipe bomb in his gas grill. While he declined to say his name out of fear, he stressed he has no idea who would want to hurt him.”But this is Lynn, these things happen,” he said.No arrests have been made in any of the cases, but McDonald said police are making strides in catching whoever is involved.”I don’t know if they have any suspects, but the police have information,” he said.A reward of up to $5,000 is being offered by Fair Plan, an alliance of insurance firms for information regarding the three incidents. Call 781-599-0232.