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(NewsNation) — Seth Rogers is calling for the nation’s top law enforcement agency to take over the investigation into the disappearance of his 15-year-old son, Sebastian Rogers.

It’s been nearly three months since Sebastian Rogers was last seen at his mother and stepfather’s home, just around the corner from where he attended classes at Beech High School in Tennessee.

“I don’t want my son to become a cold case,” Seth Rogers said during an appearance Tuesday on “Elizabeth Vargas Reports.” “The way I’m seeing things now, it’ll be a cold case.”

Seth Rogers said he’s been contacted by strangers who have said they “found stuff.” However, local officials apparently aren’t “showing up,” according to Rogers.

Seth Rogers and his spokesperson, Tony Mathis, continue to call on the FBI to get involved.

Where is Sebastian Rogers?

The Tennessee teen was last seen the night of Feb. 25 in the Sumner County home of Katie and Chris Proudfoot in Hendersonville.

Sebastian Rogers is autistic, and his mother said she heard a thud from his room around 10 p.m., about an hour after he went to bed. She added that she called out for the teen to keep it down, who responded, and she told him to “go to sleep.”

That was the last time she heard from the teen, she said. Sebastian Rogers was reported missing the following day, Feb. 26, and an Amber Alert was issued.

Chris Proudfoot was in Memphis working on a construction site the night of Sebastian’s disappearance. He said he returned home Feb. 26 after being notified his son was missing.

Seth Rogers, Sebastian’s biological father, told “Elizabeth Vargas Reports“ the circumstances surrounding his son’s disappearance do not “make a lot of sense.” 

He said the teen’s shoes were still at the front door. His Nintendo Switch was where the teen left it, and his phone was still in the kitchen.

“I still can’t figure it out,” he said.

So far, there is no evidence of foul play connected to Sebastian’s disappearance, Sumner County Sheriff’s Deputy Eric Craddock said, though he added that authorities are not ruling anything out.

Seth Rogers previously told NewsNation that he was “pretty sure” a photograph, which had surfaced online, portrayed his autistic teenage son. However, after further investigation, Seth Rogers confirmed that the teen in the photo was someone else.

Who is searching for Sebastian Rogers?

Authorities have scoured miles of land while searching for the missing teen in the days and weeks after he went missing. However, repeated search efforts have not turned up any new leads.

Sebastian’s grandparents have traveled from Texas on two occasions to help look for their grandchild. Sebastian’s grandmother, Robin Rogers, broke out in tears at a prayer vigil, recalling the teen.

“He loved to talk about plants with me,” she said. “He loved to talk about animals with me. He loved to go fishing.”

The search for Sebastian Rogers took investigators to a landfill in southern Kentucky, where the trash in Sebastian’s Hendersonville neighborhood reportedly goes after being picked up. Nothing was found during that search.

Volunteers with the United Cajun Navy, who helped search for University of Missouri student Riley Strain, have redirected some of their crews to help find Sebastian Rogers.

“Sebastian’s father reached out to us and asked for help, and so we’re going to try to help up there as much as we can,” said David Flagg, incident commander with the search organization. 

United Cajun Navy volunteers couldn’t elaborate on exactly where they were sending search crews. However, members told NewsNation local affiliate WKRN that they had drones and K-9s assisting.  

Sumner County Sheriff Sonny Weatherford told WKRN he briefly met with private investigators, who reportedly want to search some of the areas around Sebastian’s home again.

EquuSearch Midwest also offered assistance on the ground and via drone searches. 

Some strangers have become allies to Sebastian’s family. Karen Strahm and her son, Jaden Semich, took a special interest in the case from the beginning and decided to assist in the search.  

“By the fourth day, I really started to get involved. I went out searching on the fourth and fifth day, and ever since then, I’ve just been pretty vigilant with helping however I can,” Semich said. “I have children of my own, and it’s hard to not see their faces when you look at his, and I think it’s hard for every mom and dad here.”

NewsNation’s Tom Palmer contributed to this report.