PEABODY – The online memorial has begun for the Peabody High School graduate who took a fatal fall from a four-story Allston apartment building during a college party early Saturday morning.A web page commemorating the life of 21-year-old Shawn Dow is now posted on Facebook.com. The 2005 PHS graduate was pronounced dead at approximately 2:30 a.m. after police responded to the apartment building to break up a fight.Boston police spokesperson Elaine Driscoll told media outlets Saturday that officers responded to 14 Glenville Ave. on a report of a fight, and a short time later Dow fell off the building’s roof in an apparent unrelated accident.As of Sunday night, 92 people became members of the Facebook group “R.I.P. Shawn Dow” and that number kept growing.Several friends posted messages on the site, including one from Bradley DiFoggio, 20, an Allston artist who told a Boston newspaper he used to be Dow’s roommate.”I don’t know what to do without you buddy,” he wrote.Vanessa Welshons, 21, of Lynnfield, wrote her final goodbye to Dow, who she referred to as her cousin.”You’re my fav cousin Shawn, I’ll miss you, we all will.”At about 1:30 a.m., a fight occurred in the hallway outside the fourth-floor apartment where Dow was attending a party with friends, police said. However, Dow was not involved in the fight, according to Driscoll.Dow majored in photography at the Art Institute of Boston and worked in the deli at Marty’s Liquors on Harvard Avenue in Allston.An autopsy is being performed to determine an official cause of death. Police said the incident is still under investigation.