Lotte Group said Friday its vice chairman has been found dead as authorities widen a probe into corruption at South Korea's fifth-largest business group.

Lee In-won, 69, the company's highest-ranking executive outside the founding family and the top aide to its chairman, was found dead hours before a scheduled appearance at a prosecutors' office Friday morning.

"It is difficult to believe," Lotte Group said in a text message to reporters. Lee has been a Lotte man for more than 40 years since he joined the company's hotel business in 1973.

The death sends Lotte into a fresh crisis. South Korean prosecutors are investigating allegations of embezzlement, slush funds and tax evasions at Lotte Group. The investigation forced the group in June to withdraw its initial public offering plan for Hotel Lotte Co. that could have raised as much as 5.7 trillion won ($5.1 billion).

Local media reported that Lee took his own life. Yonhap quoted a note he left as saying that there was no slush fund, in an apparent response to prosecutors' allegations. Its report said a resident found his body lying on a mountain in the east of Seoul early Friday morning.

Lotte could not confirm the report. Police did not answer calls.

The ongoing investigation and the death of its long-time executive is the latest challenge for Lotte Group, with two sons of Lotte's 93-year-old founder, Shin Kyuk-ho, already embroiled in a bitter battle over control of the group.

In a rare public display of a family feud among South Korean business elites, the younger son, Shin Dong-bin, 61, last year demoted his father to honorary chairman from general chairman overseeing Lotte's businesses in Japan and South Korea. His older brother, Shin Dong-joo, 62, was removed from executive positions at various Lotte companies and then launched several failed attempts to take back the group from his younger brother.

The younger Shin, now chairman at Lotte Group, apologized publicly in June, days after prosecutors raided Lotte's headquarters. The investigation was a setback for Shin Dong-bin who had vowed to make his group and its governance transparent as public criticism mounted because of the fight with his brother.

Lee In-won was a top aide to Shin Dong-bin.

Lotte started as a chewing gum company in Japan in 1948. It now operates businesses in chemicals, food, shopping and hotels, including South Korea's largest discount and department store chains. Its brands are well recognized not only in Japan and South Korea but around Southeast Asia.