Internet sensation “Kai the Hatchet Wielding Hitchhiker” — the kooky drifter who gained fame for his stoner’s tale of saving a woman’s life — has been arrested on charges of killing a lawyer he met in Times Square.

The nomadic surfer landed spots on “Jimmy Kimmel Live” and netted millions of YouTube hits and two Facebook fan pages after he told a TV station about how he “smash, smash, suh-mashed!” a hatchet into a lunatic who attacked the Fresno, Calif., utility worker in February.

“It doesn’t matter your looks, skills or age, or size or anything, you’re worthwhile,” Kai, 34, explained at the time.

But the skateboarder, whose real name is Caleb McGillvary, is no But Union County prosecutors said the seemingly harmless hobo, prosecutors in Union County, NJ, said yesterday. He was arrested at a bus station in Philadelphia after allegedly bludgeoning Joseph Galfy, 73, to death.

He is being held in lieu of $3 million bail.

The two met in Times Square Saturday and returned to Galfy’s Clark, NJ, home where McGillvary spent the night, said prosecutor Theodore Romankow.

Galfy was bludgeoned to death at some point Sunday night, prosecutors said, and on Monday McGillvary was seen taking a train to Asbury Park, NJ.

In a graphic Facebook message posted Tuesday morning, McGillvary suggested that he had been drugged and raped.

“What would you do if you woke up with a groggy head, metallic taste in your mouth, in a strangers house … and started wretching, realizing that someone had drugged, raped … you?” the posting said.

When a fan responded he would “SUH-MASH the s–t out of them with a hatchet,” McGillvary wrote, “i like your idea.”

Galfy’s body was found Monday morning, when co-workers told police he hadn’t come to work. His neighbors said he was single and gay.

Officials said McGillvary met up with a female “fan” after the murder. His long hair had been cut short and he now has a facial tattoo.

McGillvary’s movements after that included a trip to Glassboro in South Jersey and Philadelphia.

He was considered armed and dangerous because “in the past, he has demonstrated his ability to use the back end of a hatchet,” police said.

In an interview with Vice magazine, McGillvary recounted getting into a fight in a Venice Beach, Calif., bar restroom last month and beating a man so badly that he looked like he needed surgery.

With Lia Eustachewich and AP