National Guard members have felt demoralized and that the mission has started to take a toll on them after the shooting last month in Washington, D.C., according to reports Friday.

National security reporter Haley Britzky told CNN's Boris Sanchez that the troops have expressed concerns after the shooting that left National Guard soldier Sarah Beckstrom dead and Andrew Wolfe seriously injured. Wolfe, who has been hospitalized, was reportedly showing signs of recovery this week.

Many of the troops were apparently brought on as junior service members.

"For a lot of them, this is the first time they're kind of experiencing this kind of tragedy, like we saw with the killing of specialist Sarah Beckstrom," Britzky said. "And so sources were telling us, you know, some have found a renewed sense of purpose in this mission as it's been continuing on, they feel that after this tragedy that they see a clear purpose for why they're in the city. Others are, of course, questioning even more how much this is worth it."

National Guard troops are stationed at transit centers, Union Station, along the metro, and "wondering what the purpose of all of this is."

Their families have also felt uneasy.

"And of course, the families of the service members who are here who are just reading the news, seeing the news, and are worried always about their loved ones and kind of what they're experiencing," Britzky said.

The length of deployment time has also created confusion and further damaged morale, she added.

"From the beginning of this mission, we've seen frustration that there's not really a clear timeline for how long service members will be here," Britzky said. "And there's conversation now about what that will look like. We have orders going out until February. At this point, there's a lot of expectation that will continue even further. Some officials telling us that they're kind of comparing it to the New York National Guard's mission, Empire Shield, which has been going on since right after 9/11. And so saying that that could be a potential option here. So there's really not a lot of clarity on how long this is going to go."

It's unclear how long their mission could last.

"Certainly, there's an expectation it will continue longer," she added. "But people are getting frustrated. Some service members feel that they, you know, are standing around. They don't have a clear sense of purpose. They don't really know what they're doing here. And so that's always kind of that balance of understanding why they're here and the purpose for that and carrying that mission out."