Child and privacy advocacy groups filed a complaint with the Federal Trade Commission on Thursday claiming that Amazon’s Echo Dot Kids devices are unlawfully recording and storing the conversation data of young children.

In the complaint, the coalition accuses Amazon of unlawfully storing data from conversations with children even after parents try to delete it. If true, the practice could violate the Children’s Online Privacy Protection Act (COPPA), one of the only federal privacy laws on the books. COPPA imposes certain privacy requirements for websites and services that are targeted toward children, including obtaining parental consent before a child under the age of 13’s data is collected or stored.

Amazon denies that its devices are in violation of the law. “FreeTime on Alexa and Echo Dot Kids Edition are compliant with the Children’s Online Privacy Protection Act (COPPA),” an Amazon spokesperson told The Verge.

Amazon’s Echo Dot Kids devices launched last year as a child-friendly version of the company’s other Alexa devices. However, Thursday’s FTC filing alleges that the voice-activated device collects and stores the transcripts of conversations the children have with it, along with information on what content the young users engage with on the device.

“Amazon markets Echo Dot Kids as a device to educate and entertain kids, but the real purpose is to amass a treasure trove of sensitive data that it refuses to relinquish even when directed to by parents,” Josh Golin, the executive director of the Campaign for a Commercial-Free Childhood (CCFC), the organization that spearheaded this effort, said in a statement.

A bipartisan group of lawmakers also sent a letter to the FTC today requesting that the agency open an investigation into the matter. Sens. Ed Markey (D-MA), Josh Hawley (R-MO), Richard Blumenthal (D-CT), and Dick Durbin (D-IL) said, “Children are a uniquely vulnerable population. We urge the Commission to take all necessary steps to ensure their privacy as ‘Internet of Things’ devices targeting young consumers come to market, including promptly initiating an investigation into the Amazon Echo Dot Kids Edition’s compliance with COPPA.”

The FTC received the letter, but it declined to comment.