We know D.C. Get our free newsletter to stay in the know.

The FBI confirmed this afternoon that Navy Yard shooter Aaron Alexis was armed Monday with a shotgun lawfully purchased in Virginia, despite media reports suggesting he had an AR-15 on him. At the press conference, officials also said that the time between the arrival of police on the scene and Alexis’ death was more than half an hour and less than an hour.

Valerie Parlave, the assistant FBI director in charge of the Washington Field Officealso dispelled rumors that Alexis acted with other people in yesterday’s deadly rampage, confirming that he was alone.

Alexis had been in the D.C. area since August 25 ,first jumping around various hotels and staying in Southwest since Sept. 7. He used a valid ID card to gain entry into Naval Sea Systems Command headquarters, according to Parlave, who wouldn’t say whether Alexis reported to work before shooting.

Metropolitan Police Department Chief Cathy Lanier says injured MPD police officer Scott Williams, who was shot in the leg, is in good spirits and will likely “outrun us all” one day.

She lauded the police department’s work and quick response time Monday.

“The officers that responded did an incredible job, and there’s no doubt in my mind that they saved numerous lives,” she says.

Update, 5:25 p.m. A lawyer for SharpShooters Small Arms Range in Lorton, Va., J. Michael Slocum, says in a statement that Alexis bought a shotgun there Saturday:

Sharpshooters Small Arms Range was visited by Aaron Alexis on September 14, 2013. Mr. Alexis rented a rifle and purchased ammunition which he used at the practice range. He then purchased a Remington 870 shotgun and a small amount of ammunition (approximately 2 boxes — 24 shells). In accordance with Federal law, Mr. Alexis’ name and other applicable information, including his state of residency, was provided to the Federal NICS system and he was approved by that system. After the terrible and tragic events at the Navy Yard, the Sharpshooters was visited by federal law enforcement authorities, who reviewed the Range’s records, including video and other materials. So far, as is known Mr. Alexis visited the Range only once, and he has had no other contact with the Range, so far as is known.

Photo by Darrow Montgomery