LYNNFIELD – Police Chief David Breen said town officers and State Police investigators assigned to the District Attorney’s office are working to clarify the circumstances that led to a 4-year-old girl drowning Monday evening in a swimming pool while at a Fourth of July party.Breen said Sydney Vinci, 19 Tophet Road, was discovered lying face down in the backyard pool at 7 North Hill Drive at 7:50 p.m. Breen said a family member started performing cardiopulmonary resuscitation on Vinci while another one of the 12 people attending a July 4th party at that address called emergency 911.The drowning came a little less than a year after two 2-year-old twins drowned tragically in the same town, Fire Chief Thomas Bogart said Tuesday.”It’s just a very sad and unfortunate event that has happened,” Bogart said.Steve O’Connell, spokesperson for the Essex County District Attorney’s office, said investigators believe the girl’s death was accidental, but the investigation into how she got into the pool without anyone noticing until it was too late is ongoing.O’Connell stressed the importance of remaining vigilant whenever children are near a swimming pool.”In the blink of an eye a tragedy can occur,” O’Connell said.The Fourth of July party had been going on for about three hours when the girl was discovered in the pool, but O’Connell stressed that they don’t believe “alcohol was a factor” in the tragedy.A paramedic responded to the scene just three minutes after the Fire Department got the call – and numerous police and firefighters quickly joined him – but rescuers were unable to revive the girl, who was unresponsive on a pool deck when they arrived, Bogart said.The fire chief noted three of the first responders who tried valiantly but in vain to revive the two 2-year-olds last year also responded to the scene on Monday shortly before 8 p.m.”It’s particularly troublesome and particularly disturbing when it involves young children,” Bogart said of the drownings.A critical incident team was called in last night to talk to people who responded to the drowning scene, Bogart said.”There’s some very upset emergency medical workers,” he said.Police dispatcher Michael DiCorato attempted to calm the woman caller who called 911 and asked her about efforts to revive Vinci even as he sent emergency workers to the home.Officer Bryan Materazzo, the first responder on the scene, performed CPR on Vinci for what Breen described as a couple of minutes before she was taken to Union Hospital in Lynn by ambulance.Paramedics worked to revive her on the way there, Bogart said.”They did all they could with life-saving efforts all the way to the hospital,” he said.But she was declared dead at approximately 8:30 p.m., O’Connell said.The drowning not only impacted two families but also two town neighborhoods.Well-wishers parked along Tophet Road Tuesday morning and gathered outside Steven and Trisha Vinci’s home in small groups.Steven Vinci is a local electrical contractor who lent his skills to neighbors like Cliff Tishler.”He’s helped me out a couple of times. I’m sick. I just can’t believe it,” Tishler said.Matt Devito, a neighbor of 7 North Hill Drive residents Matteo Giamarco and Christine McKenna, said the normally active street was quiet and dark after emergency workers finished their work Monday night.The side street off Lowell Street is lined with million dollar homes like the Giamarcos.’Bogart said Vinci’s family was visiting the Giamarco home when the incident occurred.”The families are friends,” he said.Town Building Inspector John Roberto stopped by 7 North Hill Drive Tuesday and said the fence surrounding the pool behind the Giamarco home is at least 5-feet high. Town ordinance requires pools to be surrounded by a 4-foot high wall or fence.”That was a secure pool,” Roberto said on Tuesday.Alan Sloan recently bought a home on Tophet Road and said news of Sydney Vinci’s death left him “terrified.”Sloan has 3-year-old twins and he said he plans to install a