WEBAug 29, 2024 · North Dakota Teen Charged with Murder: Isaac Arndt Accused of Killing 14-Year-Old Girlfriend. August 28, 2024 by Terry Fisher. An 18-year-old from North Dakota, Isaac Arthur Arndt, faces second-degree murder charges after allegedly stabbing his 14-year-old girlfriend, Jaelyn Walker, to death in Moorhead, Minnesota, near the …