Afghan national Rahmanullah Lakanwal shot Army Spc. Sarah Beckstrom twice and then used her weapon on Air Force Staff Sgt. Andrew Wolfe. His revolver had only four rounds.

"The first victim — a female guard member — was struck immediately and collapsed where she stood. She sustained at least two gunshot wounds during the ambush, the sources said.

"Then, thesuspect took her weapon and used it to continue shooting, striking the second guard member,according to multiple sources. A third guard member, who was not injured, ultimately returned fire, ending the attack."

….

"The suspect hadfour rounds in his handguninitially, multiple sources familiar with the investigation told CBS News. The revolver used in the attack was not registered to the suspect, according to investigators. Instead, itbelonged to a deceased Washington state resident. Officials saidthe number of bullets in the weapon is unusual and remains unexplained."

https://www.cbsnews.com/news/suspect-dc-national-guard-shooting-afghan-national-what-we-know/