The New Mexico attorney general’s office has asked a judge to prevent Meta from removing evidence of alleged child sexual exploitation from Facebook and Instagram, which it says is related to legal action it is taking against the company.

In court papers filed this week, attorney general Raúl Torrez requested that Meta be ordered to preserve all evidence he says was found by his investigators after they created undercover social media accounts on its social media platforms and posed as children as young as 12.

The evidence collected, which Torrez claims includes child sexual abuse material, was cited in a lawsuit filed by the New Mexico attorney general’s office on 5 December, accusing Meta of enabling adults to find, message and groom children on Facebook, Instagram and Threads, and solicit them to sell pictures or participate in pornographic material.

In the new court papers, Torrez said that one day after his office filed the lawsuit, Meta deactivated the accounts set up and used by investigators.

This was “even though the accounts at issue had operated for months without action by Meta, and even though investigators had previously reported illicit and unlawful content to Meta through its reporting channels”, the document states.

It adds: “Meta’s disabling of these accounts prevents the state from continuing its investigation into Meta’s activities. [The state] no longer had access to data within those accounts.”

In the new filing, the attorney general said that Meta had informed its office that it intended to permanently delete these accounts within 30 days and that the company intends to only preserve evidence that it deems relevant to the lawsuit.

The New Mexico lawsuit follows a Guardian investigation in April that uncovered how Meta is failing to report or detect the use of its platforms for child trafficking.

“We will of course preserve data consistent with our legal obligations,” said a Meta spokesperson. “Child exploitation is a horrific crime, and online predators are determined criminals.

“We use sophisticated technology, hire child safety experts, report content to the National Center for Missing and Exploited Children, and share information and tools with other companies and law enforcement, including state attorneys general, to help root out predators.

“In one month alone, we disabled more than half a million accounts for violating our child safety policies.”