LYNN – Police say they are investigating a string of robberies in the Highlands, where a Caruso’s pizza delivery driver was robbed at gunpoint Tuesday and another victim robbed Wednesday.Lynn Police spokesman Lt. William Sharpe said in a statement that officers spoke with the shaken delivery driver around 11 p.m., who said he was robbed in front of 163 Beaconhill Ave. by two men while making a delivery.The 44-year-old victim said he was first approached by a black male, approximately 5-feet, 6-inches tall, who was armed with a handgun and wearing a black mask. The suspect is said to have demanded money while a second suspect emerged and searched the victim, taking his cell phone, wallet and more than $100 in cash.The victim was unable to provide police with a more accurate description of the armed suspect and didn’t catch a description of the second suspect. Police searched the area, but were unable to locate the suspects.Then on Wednesday night, another robbery of a similar nature took place at gunpoint around 6:30 p.m., also on Beaconhill Avenue. The victim said two men, one believed to be a dark-skinned Dominican man, robbed him of his wallet, identification, car keys, a cellular phone and money. Both suspects were said to have been wearing ski masks and ran toward the Cook Street Playground near Allen Avenue after the robbery.A caller reported seeing a Dominican man run through his backyard on Highland Avenue a few minutes later and described him as wearing jeans and a black sweater.Lt. Dave Brown refrained to say whether the two robberies were connected, but did say officers were “trying to piece things together.”Anyone with information about the robberies is asked to contact the police at 781-595-2000. Anonymous tips can be submitted by texting the word tiplynn on a mobile device to tip411 or 847411 or from the department’s Web site at www.lynnpolice.org and clicking the “submit tip” icon.