But police, prosecutors, and an upset judge fought back hard against the intimidator - a sign that officials are no longer willing to allow the problem to fester.
Assistant District Attorney Jennifer Bretschneider persuaded the frightened witness to testify. To highlight the witness' fear, she played the voice-mail messages in court.
"It's all over the neighborhood. It's on Facebook," the jury heard the woman beg, her voice quavering. "From the bottom of my heart, please, if there's any other way, please don't make me take the stand."
The jury convicted the defendant, Darrell Johnson, 20, of West Philadelphia, of shooting a man to death in a dispute over the whereabouts of a $60 handgun. He is serving a life sentence.
Before the trial was over, detectives arrested one of Johnson's friends, Dajuan Fuller, 25, as the alleged Facebook intimidator. In March, Fuller was charged with witness intimidation, harassment, retaliation, and obstructing justice.
He is awaiting trial - held behind bars on $1 million bail imposed at the urging of the trial judge in the homicide case, Common Pleas Court Judge Renee Cardwell Hughes.
"To think that he had the audacity to come into my courtroom and think he was going to do that and nobody was going to do anything about it? Uh-uh. No," the judge said in an interview. "I will not have it."
In a series published in December, The Inquirer reported that Philadelphia had one of the nation's lowest felony conviction rates, and that a key reason was that witnesses were often terrified.
But as evidenced by the harsh treatment of Fuller, a counterattack has begun to take shape:
District Attorney Seth Williams, working with top police commanders, has revamped investigative procedures and launched a crackdown on perpetrators.
