Haruna Yukawa, a Japanese private mercenary poses in Aleppo. The Japanese national has now been captured by the ISIS militants.
Haruna Yukawa, a Japanese private mercenary, poses in Aleppo in May. ISIS claimed on Saturday that he has been beheaded.Facebook/Haruna Yukawa

Reports from Japanese news outlets suggest that its citizen Haruna Yukawa, who reportedly was captured by the Islamic State militants earlier last month, could be mentally ill.

The 42-year old Yukawa reportedly was working as a private mercenary in Syria and it is believed that he may also have fought along with the Free Syria Army before he was captured by Islamic State militants.

A Japan Times report now reveals that before heading to Syria, Yukawa had suffered a series of mental break downs.

Yukawa's mental deterioration and disorientation is believed to have been triggered after he lost his wife to lung cancer, following which he also lost a business.

At one point he had to even live in a public park after he lost his house to bankruptcy, the report noted based on details collected from Yukawa's father.

The report by the local daily that had also accessed an online journal maintained by Yukuwa, stated that due to the mental break down Yukuwa even attempted to kill himself by cutting off his genitals.

But when the suicide failed, Yukuwa thought that he was the reincarnation of a cross-dressing Manchu princess, who had spied for Japan in World War II. Subsequently, he adopted a more feminine-sounding first name-Haruna.

It was in 2013 that Yukawa first traveled to Syria and decided to open a private security firm that works for "big Japanese companies in conflict areas."

He saw the Syrian civil war as a bright business opportunity, which would be his last chance to find success in life, he told friends and family. Later this year, he also planned to head to Somalia "where the danger factor will be amped up."

"He felt his life had reached its limit," said Yukawa's father, Shoichi, 74 told the daily.

According to a Reuters report Yukuwa is the head of a Japanese security firm, PMC (Private Military Company) Co Ltd.

On his Facebook page Yukuwa has put up several pictures posing in an armored vehicle.

A video posted on 11 July show him test firing an assault fire in Aleppo.