Authorities say Anthony Wayne Raynor and Todd Allen Farmer spent March 14 partying together before they headed to a fast-food restaurant.
Investigators say that is when the two men decided to throw rocks off an interstate overpass.
"They had been smoking some marijuana, and I don't know if they were drinking either. They could have been doing both, but that was the information that we have been able to obtain," said Sheriff Moose Butler.
The rock struck Michael Vytlingam while the Canadian teenager was driving north. He is blind, brain-damaged and unable to walk.
Investigators say a tip given to Crimestoppers led them to Raynor and Farmer.
"An anonymous tip came in, and from that we were able to talk with someone else. It was kind of like a chain reaction until we actually got to the point where we could really pin the persons down that were involved in this," said Butler.
Butler says he firmly believes his department has enough evidence to get a conviction in this case.
Copyright 2022 by Capitol Broadcasting Company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.