Federal prosecutors have charged a 32-year-old Texas man with a federal firearm crime after alleging he sold the gun used in the Colleyville synagogue attack earlier this month.

Henry Dwight Williams was charged on Tuesday with being a felon in possession of a firearm, according to a statement released by the U.S. Attorney’s Office in the Northern District of Texas. Prosecutors allege he sold Malik Faisal Akram the handgun used in the synagogue standoff just two days prior to the incident.

“The Dallas FBI Field Office and our partners have worked around the clock since January 15, 2022 to determine how Malik Faisal Akram acquired the weapon he used to terrorize worshipers at Colleyville’s Congregation Beth Israel synagogue,” Matthew DeSarno, Dallas FBI Special Agent in Charge, said.

The arrest clarifies how Akram, a British national, was allegedly able to obtain the firearm used to take four people hostage at Congregation Beth Israel. Records showed he arrived in the U.S. just two weeks before the incident, and his citizenship status precluded him from legally purchasing a gun under federal law.

Through its investigation into the hostage-taking, the FBI linked Williams to Akram through a review of his phone records. They showed a series of calls between the two over multiple days leading up to the attack. According to the criminal complaint, Williams was interviewed by FBI agents after being arrested on an outstanding state warrant where he confirmed that he sold Akram the handgun.

Williams was previously convicted for aggravated assault with a deadly weapon and attempted possession of a controlled substance, according to the complaint. The complaint also said Williams told interviewing Agents that he knew he was not allowed to have a firearm and that he knew conducting the sale of the gun to Akram was illegal.

“Federal firearm laws are designed to keep guns from falling into dangerous hands,” U.S. Attorney Chad E. Meacham said in a statement. “As a convicted felon, Mr. Williams was prohibited from carrying, acquiring, or selling firearms. Whether or not he knew of his buyer’s nefarious intent is largely irrelevant — felons cannot have guns, period, and the Justice Department is committed to prosecuting those who do.”

The criminal complaint was filed in the United States District Court for the Northern District of Texas.