Former Hassan staffer in court on seven charges after arrest

Telegraph file photo U.S. Sen. Maggie Hassan, D-NH, is among the senators who were recent victims of "doxing," allegedly by former staffer Jackson A. Cosko, who is under arrest on several charges.

WASHINGTON – A former staff member for U.S. Sen. Maggie Hassan, D-N.H., was scheduled to appear in U.S. District Court Thursday, a day after he was arrested on charges accusing him of posting online “private, identifying information” of Hassan and possibly other U.S. senators.

Jackson A. Cosko, 27, a self-described “Democratic political professional” and a graduate student in cybersecurity, is facing seven charges, according to arrest reports and an affidavit filed by the lead investigator, U.S. Capitol Police Capt. Jason R. Bell.

Cosko was scheduled to appear before U.S. Magistrate Deborah A. Robinson Thursday afternoon on the charges. Five are federal charges, including one count each of making public restricted personal information; witness tampering; making threats in interstate communications; unauthorized access of a government computer; and identity theft, while the two others – second degree burglary and unlawful entry – are district charges.

Cosko had worked in Hassan’s office for about a year and a half before he was asked to resign in May, Aaron Jacobs, Hassan’s communications director, told The Telegraph Thursday.

Cosko, who had the title of legislative correspondent/systems administrator while working for Hassan, was asked to resign “for failing to follow office procedures,” Jacobs said. “We did not have reason to believe that he posed a risk.”

Jacobs said that while he and his staff cannot comment further on “an ongoing law enforcement matter,” Hassan “strongly denounces the alleged actions.”

Bell said Cosko has not had permission or authorization to be in Hassan’s office, or to access the government computers she and her staff use, since his May departure.

Cosko had worked for former U.S. Sen. Barbara Boxer, D-Calif., before joining Hassan’s staff in January 2017.

According to Bell’s affidavit, which The Telegraph obtained Thursday, the investigation that led to Cosko’s arrest began Sept. 27, when the staff of a senator identified in documents as “U.S. Senator 1” contacted the Capitol Police’s Threat Assessment Section.

The staff told authorities that someone accessed the senator’s Wikipedia page and posted restricted personal information, such as the senator’s private home addresses and personal cell phone numbers.

The practice of researching and posting restricted, private or identifiable information online is known as “doxing,” or “doxxing,” which comes from “dox,” the common online abbreviation for the word “documents.”

Around the same time, Bell stated, similar restricted information appeared on the Wikipedia pages of two other senators. He noted the “edits” to the three senators’ pages occurred “roughly contemporaneously with public – and highly publicized – Senate proceedings related to a nomination for the U.S. Supreme Court,” a reference to last week’s contentious hearing on the Supreme Court nomination of Judge Brett Kavanaugh.

It was about 10:30 p.m. Tuesday, Bell wrote, that an unidentified member of Hassan’s staff contacted Capitol Police after he or she entered Hassan’s office and found a man using a computer.

The staff member, identified as “Witness 2,” “was familiar with Cosko, and immediately recognized the man as Cosko,” Bell wrote.

When the witness “confronted Cosko, (he) typed a few keys on the computer keyboard, grabbed something from the desk, got up and left the office,” the affidavit states.

The witness then checked the computer, and found it was logged in to the account of another staff member, whom Bell identifies as “Witness 3.”

That witness, upon logging in to his or her computer, found an open web application that he or she “did not recall ever using or accessing,” Bell wrote.

He said when investigators reviewed video surveillance footage from that section of the Dirksen Senate Office Building, they allegedly saw a man they identified as Cosko enter the building carrying a black backpack.

Eleven minutes later, the video captured Cosko allegedly exiting the building, with the same backpack, and walking toward Union Station, according to Bell’s affidavit.

Further, at 10:25 p.m. Tuesday, just minutes after the man identified as Cosko left the building, Bell wrote that “Witness 2” reported receiving “a threatening email” with the title, “I own EVERYTHING.”

“The body of the email stated: ‘If you tell anyone I will leak it all. Emails signal conversations (sic) gmails. Senators (sic) children’s health information and socials,'” Bell wrote.

The alleged crimes targeting Hassan’s staff come days after multiple news outlets began reporting that someone posted home addresses and phone numbers on the Wikipedia pages for Republican senators Orrin Hatch, Mike Lee and Lindsey Graham.

It’s not known if the senators identified as senators 1, 2 and 3 refer to Hatch, Lee and Graham.

Dean Shalhoup can be reached at 594-1256, or @Telegraph_DeanS.