Updated on March 19 at 3:28 p.m.

A federal judge this month granted the U.S. Justice Department permission to surveil a WhatsApp account as part of an ongoing criminal investigation, a decision that overruled a magistrate judge who had denied the government's request to track communications over the encrypted messaging and internet calling service.

The decision by Chief U.S. District Judge Beryl A. Howell in Washington allowed the government to install so-called pen register and trap and trace devices to capture the phone numbers dialed by the WhatsApp user, identified only as “one of several subjects of an ongoing criminal investigation, and also the phone numbers or internet addresses of incoming calls.

Those devices, often referred to together as a “PRTT,” do not give the government access to the content of communications.

Howell's decision, dated March 2 but unsealed last week, overruled a February decision from Magistrate Judge Deborah Robinson, who earlier denied the Justice Department's application to use those surveillance devices on the WhatsApp user's account. Robinson, in her Feb. 5 decision, said the government needed to provide more information than just the WhatsApp account number.

Robinson specifically requested the cellular number linked to the WhatsApp account and the identity of the user's cellular service provider. Just days earlier, she had denied six other applications on similar grounds, ruling that the government was “seemingly utilizing 'WhatsApp' and 'Service Provider' interchangeably.”

The Justice Department followed up to clarify that WhatsApp account numbers are the same as users' phone numbers and that WhatsApp itself was the relevant service provider. On Feb. 28, with no response from Robinson, the Justice Department filed an objection with Howell, citing ”the need for the order as part of an ongoing investigation.”

Upholding that objection, Howell said the government had provided enough information by including the WhatsApp account number in its surveillance application.

“Importantly, the government is seeking only WhatsApp information—that is, 'information related to communications occurring over WhatsApp servers located in the United States,' rather than information regarding the cellular telephone number and cellular service provider for the user in question,” Howell wrote, quoting from the Justice Department's objection. “As already discussed, a WhatsApp account number is the same as the phone number used to create the WhatsApp account. Thus, by providing the WhatsApp account number, the government has 'provide[d] the cellular telephone number associated with the designated WhatsApp account,' thereby alleviating the magistrate judge's concerns.”

Howell cited WhatsApp's own policy for handling law enforcement requests for records. That policy, she said, notes that all requests must identify the desired records with “particularity” and include the WhatsApp account number.

“That number, which is also the cellular telephone number for the user at issue, properly was provided in the government's application,” Howell wrote.

A WhatsApp spokesperson on Monday declined to comment.

This post was updated with additional information about the judge's order.

Read Howell's ruling, posted below:

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