A Murfreesboro man drowned Sunday at Rock Island State Park after flailing his arms for help in what his friends first thought was a joke.The victim has been identified as 41-year-old Eric B. Soriano. He is the third person to drown at Rock Island in a month. Two people died in separate drowning accidents over the Fourth of July weekend.According to a report from the Warren County Sheriff’s Department, Soriano was last seen by witnesses going under the water around 5 p.m. Sunday.