Police in the nation’s capital are searching for a motive after a young intern was stabbed to death in a seemingly random attack.

Margery Magill, 27, was walking a dog along a street in Washington, D.C., when 24-year-old Eliyas Aregahegne allegedly approached her and stabbed her multiple times in her back at about 8:30 p.m. on Tuesday. Magill dropped the dog leash and managed to stumble her way across the street before collapsing to the ground and dying.

“I heard a scream and then a ‘Oh no!’ and then another scream,” Chris Chambers, a nearby resident, told NBC News4.

“Came downstairs and came out with my wife and all we saw was a dog across the street with a leash and no human and we knew something was wrong,” Chambers added. “We looked down and we found the young lady on the sidewalk in front of our house bleeding.”

Aregahegne was arrested on Wednesday and charged with first-degree murder, although Washington, D.C. Police Chief Peter Newsham said investigators remain unsure why Magill was targeted. He said she was not the victim of robbery or sexual assault and that there was no indication Aregahegne was under the influence of drugs or alcohol.

Magill attended the University of California, Davis, and was in Washington for an internship. She was walking the dog to make money through Rover, an online pet services marketplace.

Magill was raised on a small ranch in California and loved to see the world, traveling to 22 countries, spanning from Nicaragua to Tanzania, her family said. She also loved animals and interned at the Jane Goodall Institute, where she met the acclaimed primatologist, Dr. Jane Goodall, in person.

Her sister, Raeann Magill, who is still struggling to comprehend the murder, said Margery Magill thrived off the energy of the nation’s capital.

“It's absolutely tragic. I still can't wrap my head around it,” Raeann Magill said. “You know, out walking a dog and to be attacked like that. How can anyone even fathom that?”

“She loved the city. She loved the energy. She really wanted to build her career here and thrive off of the energy that was Washington, D.C.,” Raeann Magill added.