"We are shocked and saddened by the terrible news about Shain Gandee, and those involved in this tragic incident," an MTV rep said in a statement. "We are waiting for more information, but at this time, our main concern is for the Gandee family and their friends."
Continues the statement, "Our thoughts and prayers are with them. Shain had a magnetic personality, with a passion for life that touched everyone he met and we will miss him dearly."
The reality personality, 21, was discovered unresponsive in his car Monday morning with his uncle, David Gandee, 48, and another person, says Kanawha County Commissioner Kent Carper of West Virginia, where Gandee lived.
Kanawha County Commissioner Kent Carper tells PEOPLE that the family notified authorities on Sunday that they were missing since Saturday. A very intense search was done, concluding Monday morning, he adds, revealing MTV had been filming all weekend with Shain.
They had told people they were going four-wheeling in an SUV and were last seen at Larry's Bar in Sissonville, W.Va., WCHS TV reports.
According to his bio on the stunt program's website, Shain, nicknamed "Gandee Candy," was "sociable and loyal." He was his high school's prom king, and had done every job from coal mining to being a garbage man.