(NewsNation) — Two months after Tennessee teen Sebastian Rogers vanished without a trace from his home, the private investigator hired by his father believes his disappearance is the result of a “domino effect of events.”

Sebastian was last seen the night of Feb. 25 in the Hendersonville home of his mom Katie Proudfoot and stepdad Chris Proudfoot.

Seth Rogers, the missing 15-year-old’s biological father, hired a private investigator to look into his son’s disappearance, saying he still doesn’t know where his son is or what happened to him.

“There’s been really no leads that have been shared with me by law enforcement,” he told “Elizabeth Vargas Reports“ on Thursday.

Heather Cohen, the private investigator Sebastian’s father brought on to work the case, said there was a lot of “turmoil surrounding Sebastian” and called attention to December and January, saying they are key months for investigators to study.

“We know that Chris Proudfoot was in the middle of a custody battle with his ex-wife. We know that the daughter did visit over Christmas break. We know that Sebastian was with Seth during that time,” she said.

Cohen also said she knows there was a Tennessee Department of Children’s Services referral to the Proudfoot home.

“That call was likely determined to be unfounded because the case was closed and that file is restricted at this time,” she said. “I know Seth has tried to find out more about that call and he has been unsuccessful in doing so.”

Cohen also referenced “some talk” about Chris leaving Katie, alluding to what she called “trouble in paradise.”

“I feel that that probably had something to do with Sebastian,” Cohen said. “To me, these are all things that need to be considered.”

Cohen questioned how the teen would have reacted to tension in the home.

“If he overheard a conversation between Chris and Katie, where Chris is saying he can’t deal with it anymore? He’s out. Whatever, you know, that could have been an occasion for Sebastian to just leave.”

Seth Rogers said he has “mixed feelings” about whether Sebastian was safe at his mother’s home.

“I’ve heard some things,” he said.

This comes as Sebastian’s father told NewsNation that neither Katie nor Chris Proudfoot have spoken with him about the investigation.

“I haven’t spoken to them for two weeks,” he said. “They’re not talking to me.”

What happened to Sebastian Rogers?

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

Sebastian 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 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 that 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.

Katie Proudfoot said she believes someone has Sebastian.

“I feel like if he had been close to the house, or had walked off, that we would have found him by now with as many people as have been searching,” she said.

Authorities have received more than 300 tips but no answers. And his family believes that he could be anywhere at this point.

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.

Did Sebastian Rogers’ parents leave home?

Craddock said Sebastian’s mother and stepfather have been cooperative as the investigation continues, though the pair has faced questions over their decision to leave their home shortly after their son’s disappearance.

In an interview on the “Crime Stories with Nancy Grace” podcast, Katie and Chris Proudfoot were asked to confirm reports that they’ve packed up an RV and left their home in Hendersonville.

“I’m going back to work,” Chris Proudfoot said of his decision to leave.

Katie Proudfoot said she left “to accompany my husband going back to work,” adding that she planned to return home but didn’t specify when.

Additionally, Katie Proudfoot added that she’s concerned about being away while the search continues, “because my son could be anywhere and we’re looking everywhere and anywhere.”

The information from Craddock comes as Sebastian’s father tells NewsNation that neither Katie nor Chris Proudfoot have spoken with him about the investigation.

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 took investigators as far north as 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. 

“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 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 re-search some of the areas around Sebastian’s home.

EquuSearch Midwest had 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.”