Tamera Medley begged the police officer to stop slamming her head - over and over - into the hood of a police cruiser. Thinking they were helping, passers-by Shakir Riley and Melissa Hurling both turned their cellphone video cameras toward the melee that had erupted on Jefferson Street in Wynnefield, they said. But then the cops turned on them. Riley had started to walk away when at least five baton-wielding cops followed him, he said, and they beat him, poured a soda on his face and stomped on his phone, destroying the video he had just taken. Although it's legal to record Philadelphia police performing official duties in public, all three were charged with disorderly conduct and related offenses, and officers destroyed Hurling and Riley's cellphones, erasing any record of Medley's violent arrest. Echoes of the incident, which was corroborated by a half-dozen witnesses, have been reverberating nationwide in recent years as the combination of cellphone video and police officers has simmered into what is an increasingly explosive formula. The issue is gaining national attention. The American Civil Liberties Union has civil lawsuits pending in Washington, D.C., Florida, Illinois and Maryland. Last week, a federal appeals court in Boston ruled that police had violated the First Amendment rights of a lawyer who was arrested after filming cops arrest a teenager. Suits have been settled in Pennsylvania.