Not long after Volkswagen made some progress in satisfying “Dieselgate” issues with federal regulators, the automaker is now facing lawsuits filed by three highly populated states that reportedly have more than 50,000 of these vehicles — New York, Massachusetts and Maryland.

On Tuesday, the attorneys general from those three states announced lawsuits against Volkswagen as well as Audi and Porsche, saying the automakers fitted vehicles with illegal “defeat devices” that concealed illegal amounts of harmful emissions and then allegedly attempted to cover up their behavior. The action came from New York attorney general Eric Schneiderman, Massachusetts attorney general Maura Healey and Maryland attorney general Brian Frosh.

“The allegations against Volkswagen, Audi and Porsche reveal a culture of deeply rooted corporate arrogance, combined with a conscious disregard for the rule of law and the protection of public health and the environment,” Schneiderman said. “These suits should serve as a siren in every corporate board room, that if any company engages in this type of calculated and systematic illegality, we will bring the full force of the law — and seek the stiffest possible sanctions — to protect our citizens.”

These lawsuits by the New York, Massachusetts and Maryland attorneys general offices follow a nine-month-long investigation by a coalition of more than 40 states and other jurisdictions led by New York, Massachusetts and four other states. New York State’s Department of Environmental Conservation, Massachusetts’ Department of Environmental Protection and Maryland’s Department of the Environment provided important assistance with the investigation, according to officials.

The complaints allege, in detail, a cover-up that Volkswagen and Audi allegedly managed for nearly 18 months. The cover-up followed a study by researchers at West Virginia University that alerted federal authorities that these diesel vehicles emitted much more nitrogen oxides (NOx) when driven on the road than they did when undergoing emissions testing on test equipment used by the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) to test the amount of air pollutants emitted.

It hasn’t even been a month since Volkswagen agreed to two related settlements — one with the United States and the state of California and one with the Federal Trade Commission.

Federal officials explained that Volkswagen and related entities have agreed to spend up to $14.7 billion to settle allegations of cheating emissions tests and deceiving customers. They indicated VW will offer consumers a buyback and lease termination for nearly 500,000 units with 2.0 liter diesel engines from the 2009 through 2015 model years that were sold or leased in the U.S.

VW reacted to the lawsuits from New York, Massachusetts and Maryland, calling them “regrettable.”

In a message sent to Auto Remarketing, the automaker said, “The allegations in complaints filed by certain states are essentially not new and we have been addressing them in our discussions with U.S. federal and state authorities.

“Volkswagen continues to work cooperatively with the U.S. Department of Justice, the Environmental Protection Agency and the California Air Resources Board on a comprehensive national resolution of all remaining environmental issues arising from the diesel matter,” the company continued.

“To date, Volkswagen has agreed to buy back or modify affected 2.0L TDI vehicles, establish a $2.7 billion environmental remediation trust for the benefit of all 50 states, and invest $2 billion for infrastructure to increase the use of zero emission vehicles across the United States,” the company went on to say.

“It is regrettable that some states have decided to sue for environmental claims now, notwithstanding their prior support of this ongoing federal-state collaborative process,” VW added.

The trio of attorneys general claimed there are more than 25,000 VW diesel units associated with the matter in New York while another 15,000 are in Massachusetts and 12,935 are in Maryland.

“Volkswagen, Audi and Porsche defrauded thousands of Massachusetts consumers, polluted our air, and damaged our environment and then, to make matters worse, plotted a massive cover-up to mislead environmental regulators,” Healey said. “With today’s action, we want to make clear to all auto manufacturers that violating laws designed to protect our environment and our public health is unacceptable and will be punished with significant penalties.”

Frosh added, “Maryland has worked tirelessly, through Maryland’s Healthy Air Act and Clean Cars Act, as well as stringent regulations adopted by the Department of the Environment, to clean our air.

“As our complaint sets out, Volkswagen, Audi and Porsche installed defeat devices in their cars to trick regulators and to deceive the public; they did so knowing that their conduct was illegal and their misconduct has hindered our efforts to clean the air and to clean the Chesapeake Bay,” Frosh went on to say. “Their disregard for the health of our citizens and their disregard for our environment must be punished.”

The lawsuits allege that, after the EPA and CARB contacted Volkswagen and Audi about the discrepancies revealed by the West Virginia University study — which the companies fully knew were caused by their defeat devices — Audi and Volkswagen:

—Tried to cover up the problem through sham recalls that they knew would not meet the required standards

—Repeatedly failed to disclose to regulators the true reason — the defeat devices — for the discrepancies

—Only confessed to the defeat devices when they knew the regulators had them pinned to the facts

The lawsuits allege this cover-up was orchestrated and approved at the highest levels of the company, up to and including the former chief executive officer Martin Winterkorn.

“Throughout this entire course of alleged illegal conduct, in which dozens of employees, officers and senior executives were involved, the investigation found no evidence that a single Volkswagen, Audi or Porsche employee came forward to blow the whistle,” the attorneys general said.

“As alleged in the complaints, Volkswagen’s response to the scandal shows that the company has not reformed its corporate behavior,” they continued.

A copy of the complaint can be found here.