Both were taken from the scene by helicopter, police said.
The incident ended when the gunman was fatally shot by police after he brandished a weapon on the installations, Army Brig. Gen. Michael J. Talley said.
Authorities are investigating both the motive and circumstances surrounding the incident, Talley told reporters at an afternoon news conference. Here’s what we know so far:
How the day unfolded
Frederick Police Chief Jason Lando said the first shooting took place at “a military institution” in the Riverside Tech Park.
In a news release, the police department said the building is a warehouse rented by Naval Medical Research Center, Biological Defense Research Directorate to store research supplies and equipment.
After the shooting, a victim entered a nearby business, Nicolock Paving Stones, and asked for help, a person there said.
“Our team was able to assist them and called the authorities,” a statement released by Jeremy Mutschler, director of marketing and advertising at Nicolock, reads. The statement emphasizes that the shooting did not happen at Nicolock
The gunman was stopped at the gates of the installation, but before the vehicle could be searched the shooter took off.
He was stopped about 1/2 mile onto the installation, where he got out of the car, brandished a weapon and was shot by police, Talley told reporters.
Frederick Police Chief Jason Lando said the gunman used a rifle but did not provide any additional information on the weapon.
Frederick is about a 50-mile drive northwest of Washington, DC. Woldesenbet was an E-4 rank and did not live on Fort Detrick, officials said.
Agencies helping Frederick police include the FBI; the Bureau of Alcohol, Tobacco, Firearms and Explosives; Maryland State Police; and the Frederick County Sheriff’s Office.
The FBI is handling the first shooting scene, officials said.
CNN’s Jason Hanna, Melissa Alonso, Joe Johns, Amanda Watts and Michael Callahan contributed to this report.