The teen suspected of fatally stabbing Barnard College freshman Tessa Majors is believed to have skipped town to hide out with relatives, The Post has learned.

“We think he’s down South. We’re looking for him,” one high-ranking source told The Post.

He is not believed to have left the city on a train or airplane, suggesting he traveled by car, the source added.

The New York-New Jersey Regional Fugitive Task Force, comprising dozens of local and federal law-enforcement agencies, has been tapped to find the boy, sources said.

The 14-year-old suspect, whom cops have not publicly identified because he is a juvenile — but whose photo they have released — has been on the run since early last week, when he bolted from a car while on his way with a guardian to talk to cops, sources have said.

Police have publicly disputed that account, but high-level law-enforcement sources confirmed the story to The Post again Tuesday.

Cops could be tracking him via cellphone or social media, or he could be eluding them by avoiding tech, a former NYPD investigator said.

“If he stays off the grid, that’s pretty remarkable,” the source said, noting teenagers’ inclination to spend hours every day on social media.

Police arrested Zyairr Davis, 13, on a felony murder charge after he allegedly admitted to his role in the botched mugging in Morningside Park on Dec. 11.

Majors, a musician and aspiring journalist, was walking in the upper Manhattan park when she was jumped, put in a chokehold and stabbed numerous times, according to police.

The 18-year-old Virginia native was found by a Columbia University security guard just outside the park with stab wounds to her face, neck and arms, at around 5:30 p.m., according to police.

Another 14-year-old was detained last week, but was released for lack of evidence.