The former contract security guard accused of stealing a “substantial” number of guns and gun parts from the Bureau of Alcohol, Tobacco, Firearms and Explosives quietly turned himself in to authorities the day after he skipped his initial court appearance, according to a new court filing.

Christopher Lee Yates of Martinsburg, West Virginia, had been under a warrant for his arrest after he failed to appear at the U.S. District Court on Wednesday morning. At approximately 3:30 p.m. on Thursday, March 21, Yates came by himself to the offices of the U.S. Marshal Service in town. “Nothing sexy, he just walked in and surrendered,” said Alex Neville, the Chief Deputy Marshal for the Northern District of West Virginia.

After spending the night in jail, Yates appeared before Judge Robert Trumble on Friday morning, according to court records. He will be arraigned on March 26. He will remain in federal custody until then, according to Stacy Bishop, a spokeswoman for the U.S. Attorney’s Office for the Northern District of West Virginia.

Yates was arrested in late February after ATF agents discovered that a pistol slide recovered by local police was a decommissioned federal service weapon that should have been destroyed at the Martinsburg facility where Yates worked. Among the weapons he allegedly stole was a fully automatic FNP90 submachine gun, as well as at least two semiautomatic pistols. According to an indictment, he had sold stolen guns and parts since at least February 2017.

In a letter sent to the ATF on March 12, Senators Ron Johnson of Wisconsin and Gary Peters of Michigan asked the agency for more details on the crime. The senators said sources had advised them that Yates had stolen as many as 600 firearm parts, valued at $70,000. The ATF has until March 26 to respond.

The ATF declined to provide details on just how far afield the weapons Yates is accused of stealing have turned up. In an email, ATF spokeswoman April Langwell said that the agency has recovered weapons and parts connected to the case “across the country,” suggesting that authorities have found the stolen goods in multiple states.