Wickr Me, an Amazon-owned encrypted chat platform, stopped accepting new users after Saturday and will shut down completely on Dec. 31 of this year, the company announced.

The decision, first announced in November, follows several controversies surrounding the ultra-secure chat app, which allowed users to sign up without a phone number or other potentially identifying information, making it a favorite for security-minded groups including hackers, drug dealers and journalists.

In June, an NBC News investigation revealed that Wickr Me had become a go-to product for many people trading child sexual abuse material. The investigation identified 72 court cases from the past five years in which the defendant allegedly used Wickr (as it’s commonly known) to trade child sexual abuse material. Law enforcement officials and a representative for the National Center for Missing and Exploited Children told NBC News at the time that Wickr wasn’t doing enough to detect or report the trading of such material on its platform.

In a statement provided to NBC News in June, an Amazon Web Services spokesperson said: “Amazon is committed to preventing child sexual abuse material (CSAM) in every segment of our business, including Wickr, which maintains strict Terms of Use that clearly prohibit illegal activity. We act quickly on reports of illegal behavior, respond immediately to requests from law enforcement, and take the appropriate actions. Anyone found to be in violation of our terms is subject to account termination.”

“Wickr absolutely responds appropriately to, and cooperates with, law enforcement on these critical matters,” the spokesperson said.

In its statement in November, the company explained that it was shutting down Wickr Me to devote more resources and focus toward its business-to-business products, AWS Wickr and Wickr Enterprise. The post did not mention the business it has with government agencies, including the Department of Defense and the Department of Homeland Security.

When NBC News tried to create a new test account on the app on Sunday, it displayed a pop-up saying: “Wickr Me will not support new users starting 31-Dec-2022. Wickr Me will be unavailable after 31-Dec-2023.”

Wickr was founded in 2012, applying high-level encryption to a consumer-messaging product. By 2015, the company had raised $39 million in funding. That same year, numerous outlets reported that the Islamic State terrorist organization was using the app to recruit new members. In 2016, one of the first successful prosecutions against someone trading child pornography on the app was reported by the Deseret Morning News.

In June 2021, Wickr was acquired by Amazon Web Services. Since the acquisition, the company had faced questions about its government contracts with agencies like Customs and Border Protection and attracted attention with its role in records-related scandals in which the app was used to automatically destroy government communications.