The Jacksonville Sheriff's Office arrest for a man they said stabbed his relative early Saturday morning.
It happened around 7:20 a.m. in the 5700-block of West 35th Street near Moncrief Road, according to detectives.
Police said 55-year-old Reginald Adams was punched and stabbed by his grandson, 26-year-old Alfred Johnson, in some type of argument.
Witnesses told police Johnson then drove off in Adams' car.
Johnson was arrested about 8 p.m. Saturday.
Police said Adams was taken to Shands Medical Center with life-threatening injuries.