The grandmother of a Louisiana man charged in a fatal hit-and-run was arrested for obstruction of justice Monday after authorities determined she helped her grandson flee the scene.

Hunter Mason Johnson is accused of hitting multiple vehicles and construction worker Brady Ortego with a Ford pickup truck while driving along Interstate 310 early in the morning of Jan. 14, according to a news release from the Louisiana State Police.

The 44-year-old was thrown from the Hale Boggs Bridge in St. Charles Parish into the Mississippi River, police said. His body has yet to be recovered.

Police said Johnson, 22, left his truck on the shoulder of the highway after the crash and fled on foot. State troopers discovered that he contacted his grandmother, Marie Sally Dufrene, to pick him up, which they say “prevented investigators from making an arrest at that time.”

The 73-year-old was booked into the Nelson Coleman Correctional Center. Johnson was arrested March 12 on charges including vehicular homicide while driving under the influence and hit-and-run driving involving a fatality.

It was not immediately clear if they had attorneys who could speak on their behalves.