Like the Observer – the strange man who keeps popping up during investigations then disappearing – “Fringe” has mysteriously vanished.

The Fox drama has made plans to leave New York, where a tax credit for TV and movie production is likely ending, and move to Vancouver, if it comes back for a second season.

But even before the show got ready to leave the Big Apple, the sci-fi flavored thriller vamoosed from the Tuesday TV schedule.

But “Fringe” will be back on April 7. And before the show’s first season ends, we will see Observer again, according to executive producer Jeff Pinkner.

“I can’t say when,” he added.

That’s not the only question that was left dangling by the show’s most recent episode, which aired Feb. 10.

Does FBI agent Olivia Dunham (Anna Torv) actually have unexplained abilities, thanks to a drug she was given as a child? (Pinkner wouldn’t confirm, but he did say that when the show returns, the third episode will delve into her personal history.)

More important, who – or what – is Mr. David Robert Jones (the terrific Jared Harris)?

The last we saw of him, the mysterious and seemingly powerful Jones, who has been orchestrating various bizarre and deadly crimes that Olivia and her team have investigated, appeared to be dying while in the custody of FBI.

But then he escaped from the hospital – through a hole in the wall.

“He’s still human,” said Pinkner. He cackled a bit, indicating that there is much more to be learned about Mr. Jones.

That character has been a great addition to the show, which has been both ambitious and inconsistent.

Some episodes in “Fringe’s” first season have been predictable and formulaic. But there have been some excellent episodes later in the show’s run, notably “The Arrival,” which featured the freakishly compelling Observer, and the suspenseful Feb. 10 episode, in which Jones played a large role.

And the show’s Dec. 2 episode, “Safe,” showed a new side of Dunham. Hanging out in a bar with Peter (Joshua Jackson), she went from being a businesslike, square FBI agent to a woman who you’d actually want to spend time with.

One thing “Fringe” hasn’t had a problem with is shocking and suspenseful openings. It’s just that what has followed wasn’t always as tantalizing.

“We found that, absolutely, early on, we were falling into the trap of, the tease would be fantastic. And then we would too quickly answer it and (reduce) the tension,” Pinkner said.

The goal now is to “have the energy of the show get bigger as (an episode) goes along,” he said.