South Dakota Highway Patrol along with McCook and Hanson County authorities began a search around 3:00 a.m., Saturday, for a 31 year old runaway prisoner.
It happened at the Fuel Mart off I-90 just a few miles south of Spencer, SD.
The inmate is 31 year-old Oscar Antonio Herrera-Menjivar who is originally from Mexico but being taken from Florida to a facility in Nebraska.
He is 5'5'', 140 lbs. with black hair and brown eyes.
Authorities tell us he may be wearing an orange prison shirt or a blue one with shorts and black shoes.
He was convicted of a sexual assault involving a minor.
Herrera-Menjivar is one of thirteen prisoners being transported to different facilities in a private prison-transport van.
When the van stopped near Spencer, SD, McCook authorities say he took off running and headed south.
McCook County Emergency Management personnel set up a command post trailer for crews as they began their search.
Several agencies have teamed up in this effort, many of the crews went door-to-door within a few miles of the gas stop.
One of their goals is to make sure you know what's going on. Authorities also want to see if they can find any new information as to where he might be.
Lt. Paul Gerken with the SD Highway Patrol tells us why.
"We do consider him to be dangerous because he is on the run from law enforcement but we put out the warning to people telling them to consider him dangerous because he does want to get away from law enforcement and he doesn't want to get caught," Lt. Paul Gerken said.
Authorities want to warn you: if you're traveling, or live in the area, be on the look-out and don't pick up a hitch-hiker in the area.