Facebook has been under investigation by California officials over its privacy practices for more than a year, the state attorney general Xavier Becerra said on Wednesday, and may now be forced to turn over key documents.

In a press conference on Wednesday, Becerra said the attorney general’s office has been investigating since spring 2018 whether Facebook violated California law by “deceiving users and misrepresenting its privacy practices” and that the company has continued to “drag its feet” and refused to comply with requests.

The investigation included a subpoena for documents related to the Cambridge Analytica scandal, which, as the Guardian has reported, included improper data practices by the third party data firm. Facebook has not provided a response to 19 interrogatories or the six document requests issued by the attorney general’s office over the past 18 months.

“If Facebook had complied with our legitimate investigative requests, we would not be making this announcement today,” Beccera said.

The office requested executive communication regarding auditing third party developers’s access to data, advertising policies and emails between Mark Zuckerberg and Sheryl Sandberg regarding Cambridge Analytica.

The investigation comes as Facebook faces increasing scrutiny following a number of privacy-related scandals. In July the company was fined $5bn for violations related to Cambridge Analytica and in October the chief executive, Zuckerberg, faced hours of interrogation in Congress over the company’s proposed cryptocurrency venture, Libra. Across the US there are 47 attorneys general investigating Facebook for antitrust violations.

“This is important when you consider the personal information that we all supply to Facebook, every single day,” Beccera said. “Facebook knows some of the most intimate details of our lives – from our new job, or a new marriage, or to the death of a loved one, or birth, a child”.

If the court determines Facebook has indeed not been responsive to the attorney general’s investigation, it can force the company to turn these documents over to investigators.

Meanwhile, Beccera encouraged anyone with information regarding misconduct by Facebook to call a number to report it. He implied that under the California Consumer Privacy Act, set to be put into action in January 2020, there will be more enforcement of these kinds of protections.

“This is the only law we have in America to help protect your privacy in meaningful ways, so it will be a watershed moment come next year when this law takes effect and we are able to start enforcing,” he said.

Facebook did not immediately respond to request for comment.