Lotte vice chairman Lee In-won found dead

Local media said a suicide note was found in Lee In-won's car

The vice chairman of South Korea's Lotte Group has been found dead hours before he was to be questioned in a corruption probe.

Police investigators said the cause of death appeared to be suicide.

The 69-year-old was due to be questioned on Friday in an inquiry into a possible slush fund and financial irregularities in the company.

Lotte has joint headquarters in Japan and South Korea, and owns businesses from hotels to chemical manufacturing.

According to local media, investigators found a four-page suicide note in his car.

Mr Lee was one of the most senior executives in the Lotte Group, holding the highest position outside the founding family that still runs the firm.

He was also the closest aide to chairman Shin Dong-bin, who is embroiled in a family feud with his older brother over control of the company founded by their father.

In a statement, Lotte Group said: "He (Lee) oversaw Lotte Group's overall housekeeping and core businesses and accurately understood the minds of Chairman-in-Chief Shin Kyuk-ho and Chairman Shin Dong-bin."

Lee In-won (right) was a close ally to chairman Shin Dong-bin

In June, prosecutors reportedly raided Lotte offices to investigate the suspected slush fund and allegations of breaches of trust regarding transactions between the conglomerate's companies.

About 200 officials searched Lotte's headquarters in Seoul, several subdivisions of the firm and the homes of key executives, local media said at the time.

It is not clear where this death leaves the investigation.

Lotte Group is involved a variety of sectors including hotels, chemicals, food and retail.

It is Korea's fifth-largest conglomerate and is considered one of Korea's family-run "chaebols" which are known to have complex ownership structures.

Analysis: Stephen Evans, BBC Korea correspondent

Lotte, like other big South Korean companies, is owned and controlled primarily by one family.

But the vice-chairman, Lee In-won, - now deceased - was a trusted outsider who had worked for the company for four decades.

Before Mr Lee's death, South Korean prosecutors were investigating the source of hundreds of millions of dollars in family accounts.

Lotte, like other giant South Korean conglomerates is a maze of companies, with exact ownership unclear. The allegation was that money moved invisibly - and illegally - between the 60 subsidiaries, and from company accounts to personal accounts of family members.

The dead man was a loyal servant of the family and the company, privy to its secrets. South Korean media said he left a suicide note saying the chairman for whom he worked was innocent of wrong-doing.

South Korea has the highest rate of suicide among the industrialised OECD countries.

On the latest figures, the country had 29 suicides for every 100,000 people, compared with 22 per 100,000 in Hungary (the next worst) and 19 in Japan.

The reason isn't clear. Part of it may be the ancient weight put on personal shame in the culture. But some also blame the high pressure to succeed.