All the news websites of the Embarcadero Media Group, including the Palo Alto Weekly, are up and running again after unknown hackers disabled access Thursday night.

Embarcadero Media Group is the parent company of several local media outlets.

According to Palo Alto Weekly editor Jocelyn Dong, the hacking occurred around 10:30 on Thursday night. The perpetrators reconfigured the websites so that anyone who tried to visit the site was confronted with an image of a person wearing a Guy Fawkes mask, a symbol of the activist group Anonymous that has gained prominence over the past few years for orchestrating major online security breaches.

A message below the image explained that “Embarcadero Media Group (Almanac) has failed to remove content that has been harmful to the wellbeing and safety of others,” and warned that “Failure to honor all requests to remove content will lead to the permanent shutdown of all Embarcadero Media Group Websites.”

The hackers ended their message by stating “We do not forgive, we do not forget, we are legion.”

Though the perpetrator referred vaguely to content as the reason for their attack, the Embarcadero Media Group does not know the actual motive.

“We have no idea what article or other content precipitated this attack,” said Bill Johnson, the company’s CEO. “There has been no recent request to remove anything. We therefore have doubts that this was the real motivation behind the hacking.”

According to Lieutenant Zachary Perron of the PAPD, the attack does not seem to be part of any larger movement.

“This appears to be an isolated, targeted incident against a single business [the Embarcadero Media Group],” Perron said.

Because the investigation is ongoing, Perron says that the police are unable to release additional information at this time.

According to Johnson, other law enforcement agencies will become involved in the investigation.

“The FBI has primary jurisdiction,” Johnson said. “If the FBI were to decide to not pursue an investigation, then the multi-agency Santa Clara County cyber-crime task force would take charge.”

According to Dong, the Information Technology department of the Embarcadero Media Group disabled the websites after the sites had been breached, taking down the graphic and message posted by the hackers.

Johnson explained that Embarcadero Media Group had put in place measures to preserve data in the case of a website crash.

“We have robust back-up and other measures that preserved all our data and allowed us to get the websites back online,” Johnson said.

He emphasized that the hacking was likely the work of a skilled cybercriminal.

“This attack was a very well-planned and calculated attempt to inflict maximum disruption on our operations,” Johnson said.