When he was 20 years old, Harel Hershtik planned and executed a murder, a crime that a quarter of a century later is still widely remembered for its grisly details.

Today, he is the brains behind an Israeli health-tech startup, poised to make millions of dollars with the backing of prominent public figures and deep-pocket investors.

With his company set to go public, Hershtik's past is coming under new scrutiny, raising questions about whether someone who took a person's life deserves to rehabilitate his own to such an extent.

'When I was young, I would say that I was stupid and arrogant,' said Hershtik, now 46. 'You can be a genius and yet still be very stupid and the two don't contradict each other.'

Today, Hershtik is the vice president of strategy and technology at Scentech Medical, a company he founded in 2018, while behind bars, which says its product can detect certain diseases through a breath test.

Hershtik demonstrates his company's product, which he says can detect certain diseases by analyzing a patient's breath, at the company's office in Rehovet, Israel, May 3, 2022.

In a three-hour interview with The Associated Press, he repeatedly expressed remorse for his crime.

Hershtik was convicted of murdering Yaakov Sela, a charismatic snake trapper he met when he was 14. The two had a bumpy relationship.

Sela was known for having numerous girlfriends at once, one being Hershtik's mother. Hershtik said he felt uneasy with how Sela treated some of the women, including his mother.

In early 1996, Sela discovered that Hershtik had stolen 49,000 shekels (about $15,000 at the time) from him, and the two agreed that instead of involving the police, Hershtik would pay him back double that amount. Court documents say Hershtik instead planned to murder Sela.

Pulled over during a drive to gather the money, an accomplice of Hershtik's fired three shots at Sela, using Hershtik's mother's pistol. He then handed Hershtik the gun, according to the documents, and Hershtik shot Sela in the head at close range.

The pair shoved Sela's body into the trunk and buried it in a grove in the Golan Heights, according to the documents. Weeks later, hikers saw a hand poking up from the earth, and Sela's body was found.

The sensational crime gripped the nation.

In court documents, prosecutors say Hershtik lied repeatedly in his attempt to distance himself from the murder.

Hershtik said he was compelled to lie so that he could protect the others involved in the scheme, which included his mother.

Hershtik was sentenced to life in prison for premeditated murder and obstructing justice, among other crimes.

He would serve 25 years, during which time Hershtik earned two doctorates, in math and chemistry, and got married three separate times. He said he established 31 companies, selling six of them.

But prison was also a fraught time for Hershtik. He said he spent 11 years in quarantine because of health issues. He was punished twice for setting up internet access to his cell, in one case building a modem out of two dismantled DVD players.

Last year, a parole board determined he had been rehabilitated and no longer posed a danger to society.

As part of his early release and until 2026, he is under nightly house arrest from 11 p.m. to 6 a.m. He must wear a tracking device around his ankle at all times and is barred from leaving the country.

A free man, Hershtik sat recently with the AP in his office in the central city of Rehovot, Israel.

His start-up is waiting for regulatory approval to merge with a company called NextGen Biomed, which trades on the Tel Aviv Stock Exchange and would make Scentech public.

Hershtik said the company's product is being finalized for detecting COVID-19 through a patient's breath, and it is working to add other diseases such as certain cancers as well as depression. The product is meant to provide on-the-spot results in a non-invasive way.

The company has received a patent for its technology in Israel and said it is preparing to apply for FDA approval soon.

Hershtik said the merger values the company at around $250 million and that he has raised more than $25 million in funding over the last two years through private Israeli investors. A large part of the investment is from Hershtik's own money, although he won't say how much. Prisoners in Israel aren't barred from doing business, but

Hershtik's success is rare.

His company is backed by prominent Israeli names, including Yaakov Amidror, who chairs NextGen and is a former chief of the country's National Security Council.

'According to the rules of the country, the man is allowed to rehabilitate. He paid his price and he rehabilitated. So there is no reason not to help him rehabilitate,' Amidror, who testified to the parole board on Hershtik's behalf, told the AP.

But Hershtik's past is already haunting him. Hershtik was demoted from CTO earlier this year to his current position, in part because he didn't want his crime to scare away investors.

'Harel has always said if for some reason his presence is a problem and the company would be better off without him, that he's willing to leave the company,' said Drew Morris, a board member and investor.

As Scentech seeks to take its product to market, investors will need to decide whether Hershtik's rap sheet influences where they put their money.

Ishak Saporta, a senior lecturer at Tel Aviv University's Coller School of Management, said he believed investors would be drawn to the company's potential for profit rather than deterred by Hershtik's history.

'What concerns me here is that he became a millionaire. He paid his debt to society in jail. But does he have a commitment to the victim's family,' Saporta asked.

Tovia Bat-Leah, who had a child with Sela, suggested he help fund her daughter's education or create a reptile museum in Sela's name.

'He served his time but he should also make some kind of reparation,' she said.

Hershtik sees the good that could come about from the company as the ultimate form of repentance. He said he could have used his smarts to create any sort of company with no benefit to society but chose health tech instead.

'Trust me, this is not for the money,' he said.