FARMINGTON — A 4-year-old boy from Mittenrock died on Monday in a rollover car crash south of Shiprock.

Kaden Augustine was killed as a result of the wreck. The boy's grandmother, who was driving the car, was allegedly intoxicated at the time of the crash. FBI agents charged her Wednesday with involuntary manslaughter in connection to the wreck, FBI spokesman Frank Fisher said.

At 9 p.m., Patricia Benally, the grandmother, crashed the Chevrolet Cavalier she was driving at mile marker 72 of U.S. Highway 491. It was a rollover crash and didn't involve any other vehicles, according to the criminal complaint against her.

Benally's 4-year-old son and her daughter, Audrey Benally, 21, were in the car, along with Audrey Benally's three children, Kaden and a 2 and 3 year old.

Patricia Benally was allegedly driving south at a high rate of speed when she crashed the car, which came to rest in the center median, according to court documents.

The family visited the Rio Grande Zoo in Albuquerque the day of the crash. On the way home, Patricia Benally said she drank a miniature bottle of alcohol in Cuba and some malt liquor and took capsules to fight a cold, according to the complaint.

Patricia Benally told investigators that she must have fallen asleep at the wheel, and she remembers waking up driving on rumble strips just before the wreck.

Patricia Benally shattered her elbow and suffered other injuries in the crash. The condition of the other passengers wasn't available Thursday.

According to court documents, a blood test at the Northern Navajo Medical Center in Shiprock taken after the crash showed Patricia Benally's blood-alcohol concentration was .237, which is nearly three times the legal limit for operating a motor vehicle.

The U.S. Attorney's Office for the District of New Mexico filed a motion to have Patricia Benally detained, pending trial on Thursday. The motion states she is a flight risk and a danger to the community, according to court documents.

Fisher said Patricia Benally has a detention hearing on Friday.

Ryan Boetel covers crime for The Daily Times. He can be reached at 505-564-4644 and Follow him on Twitter @rboetel on Twitter.