Riley Strain's family is expressing frustration toward his fraternity brothers.
Nearly a month after the University of Missouri student's body was found in Nashville's Cumberland River, his mom Michelle Whiteid criticized the Delta Chi brothers' response. Specifically, she questioned why the fraternity members who were in Nashville with Riley when he went missing March 8, had not called the police when they informed her he had vanished.
"Why wouldn't they have called the police when they got back at 3:15 in the morning and didn't see him then?" Michelle said during a joint appearance with her husband Chris Whiteid, Riley's father Ryan Gilbert and stepmother Milli Gilbert on NewsNation April 16. "I don't know."
And Chris emphasized that the fraternity brothers did not involve the authorities until nearly 14 hours after his stepson was last seen.
"We called them on the way down," he explained. "It was probably close to 12 o'clock and they were just going to the Sheriff's office to report him missing."
Michelle and Chris also felt abandoned by Riley's friends soon after their March 9 arrival in Nashville.
"So when we got there, several of the boys were out front with a police officer," Michelle continued. "The boys stayed out for a while and then they all of a sudden disappeared."
Noting the frat's plans to continue with the event that brought them to Nashville, she tearily continued, "They ended up back out a little while later in their dress clothes to go out to their formal that night."
Chris recalled that he and Michelle went out to conduct their own search through several Nashville hospitals for hours before returning to the hotel where Riley's fraternity had been staying.
"We come back and they're coming back, some of them from the party and they're waving at us as we're sitting in the truck," he added. "How does that make you feel?"
And while Chris added that the fraternity brothers initially offered their support, they did not follow through in helping the family.
"We didn't know what we needed at that point in time," he expressed. "But you would've thought that they would've at least been out searching, trying to do something. It wasn't."
Riley's father Ryan added, "We weren't very happy with them to say the least. It's appalling."
In the near month since the search for Riley concluded, Michelle said the family still has not had a formal conversation with her son's fraternity brothers, and she feels like the organization "maybe" has information they have not disclosed about the night Riley disappeared.
"I haven't sat down and talked to any of them to say ‘Tell me your whole entire story,'" she said. "Would I like that? Yes. It would be nice."
And Chris interjected, "I don't understand why they wouldn't have reached out to us, wanting to provide information from that night. Maybe I'm crazy, but why should we have to reach out to them and beg them for information on a missing brother?"
Read on for a full timeline of the family's search for answers regarding Riley's disappearance and death.
E! News has reached out to University of Missouri and its Delta Chi chapter for comment but has not heard back.