(CNN)Of the two sailors injured in a shooting Tuesday near a military installation in Frederick, Maryland, one remains in the hospital and one has been released, authorities said.
2 sailors were injured in a shooting near Maryland's Fort Detrick. Here's what we know
US Navy Hospitalman Casey Nutt, 26, was released from a trauma center on Tuesday night, and Hospital Corpsman 1st Class Carlos Portugal, 36, remains at the trauma center in critical condition, according to a press release Wednesday from local and federal authorities.
Both victims were taken from the scene by helicopter, police said.
The Navy identified the gunman as Fantahun Girma Woldesenbet, a Navy hospital corpsman who was fatally shot by police. Fort Detrick officials told CNN he was posted at that installation.
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 a Tuesday afternoon news conference. Here's what we know so far:
Police were called to the first scene, about a 4-mile drive east of Fort Detrick, around 8:20 a.m., Lando said earlier. "We know some people fled from the business," Lando said.
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.
Officials identified that individual as Nutt.
Portugal was found in the warehouse where the initial shooting occurred, the release said.
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.
Garett Wagner, the operations manager at Nicolock Paving Stones, was talking over pricing changes with a new salesman when Nutt ran in, his military fatigues covered in blood.
"I've been shot. Please help me. There's an active shooter, he's still chasing me," Wagner said the man told him.
Wagner said he quickly went into action, telling Nutt to get in the bathroom and close the door. The salesman and another employee locked the front door, he said.
"I can't tell you if I was scared or fearful or trying to help," Wagner said. "I don't know."
Wagner said he had all employees gather in the back, telling them to shut the door until he got back.
The manager called 911, but another employee had already called.
"You don't think it's going to happen here ... then it did, and it happened," Wagner said. "Did we do the right thing? Did we do alright? I think so. I don't know."
Frederick Police Chief Jason Lando said the gunman used a rifle but did not provide any additional information on the weapon.
Fort Detrick is an Army biomedical and research facility. There are elements of other military branches on the post. According to the website Military Installations, there are about 1,300 active-duty military and 8,500 civilians and contractors at Fort Detrick or the Forest Glen campus in Silver Spring, Maryland.
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.