Philadelphia police are investigating an Instagram account that may have been used to intimidate witnesses testifying in criminal cases.

The Instagram account, rats215, has since been shuttered, but the Philadelphia Inquirer reported that the anonymous account had about 8,000 followers and had posted photos, statements to police and witness testimony. The account encouraged followers to send documents to expose “rats,” and in one case it threatened people who went to the police. More than 150 photos were posted to the account.

Rats215 was discovered online last week when a Philadelphia police officer combing through Twitter found photos of witnesses in a 2012 attempted shooting, according to the Inquirer. The find led the officer to the Instagram account.

Prosecutors acknowledged that there is an investigation underway but declined to comment on details of the probe.

"We work with Philadelphia police to investigate vigorously and thoroughly any attempt to intimidate any witness, to identify perpetrators, and, where appropriate, arrest and prosecute,” Tasha Jamerson, a spokeswoman for the Philadelphia district attorney’s office, told the paper. She said that witness intimidation is “a very serious, ongoing problem.”

Witness statements from the 19-year-old attempted shooting victim from 2012 were among the  posts to the rats215 Instagram account. Investigators are trying to determine how the account got hold of the statements, which were made in secret grand jury proceedings.

"These actions shoot an arrow through the heart of the criminal justice system, placing victims and witnesses at risk," Philadelphia Police Lt. John Walker told the Inquirer. "[Accounts like rats215] should be voluntarily removed by the host of such sites."

The rats215 Instagram account was no longer active by Thursday night, after the Inquirer contacted the social media photo sharing site.