Casteel is accused of shooting at a vehicle on Oct. 18 on Interstate 96 near Howell.
The Local 4 Defenders have learned a tipster, who herself was shot at while driving, provided crucial information. She called 911 on Oct. 18 from I-96 near Howell to report what she thought may have been a gunshot directed at her vehicle.
The 24-year-old woman told police she was a victim of a road rage incident. She gave a brief description of the vehicle and not much more.
She was driving her father's vehicle and did not want to make a big deal of the incident. Days passed and one after another person came forward to say they were victims of a mysterious I-96 shooter. More than 20 people reported incidents.
The original tipster was interviewed again. She still gave little information. Then, on Sunday, Oct. 28 she went to police to reveal critical information about the gunman's license plate. That helped police tie it all together.
Casteel's family members have said he battled depression and mental health issues. He apparently has become very vocal regarding his anger toward the government. Police say they believe he was not just trying to scare people but he was trying to take them out.