For the past year, New York-based Natalie Keyssar has been photographing the Black Lives Matter movement as it spread across the country. She was in Ferguson, Mo., after Michael Brown, an unarmed black man, was killed by a white police officer. She traveled to Baltimore when Freddie Gray died while in police custody last April. And she covered the aftermath of Eric Garner's death in Staten Island, N.Y.

So when Time Magazine asked her to embed with the police officers of West Philadelphia's District 19 for a week, she didn't hesitate. "As a photojournalist my interactions with police are almost always quick and frequently during moments of high tension, so having this time to see how they work, hear how they feel, and see what their daily lives are like during this pivotal moment for policing in America, was an amazing opportunity," she tells Time.

During her assignment, Keyssar would spend more than 12 hours a day with police officers, often on patrols. "I'd arrive at the station most days between 10:00 a.m. and noon, which allowed me to catch three different patrols each day," she says. "I spent the rest of my time at the station, photographing officers [as they] do paperwork, eat bagged lunches and talk about their experiences on the street."

After her week spent in that district, Keyssar feels her perspective on the police has changed. "I've spent a lot of time in my career standing next to protesters, and I've seen police from that side — they are sort of a caricature [from that side]. They are doing a job and they are sort of representing a system. They are not allowed to express their feelings and that can be dehumanizing," she says. "I think, after this assignment, I'll carry that more human perspective. Whether these people are representing the system or not, and whether there are failures within that system that need to be addressed, there are also human elements that I feel are…forgotten."