Overnight, police told Attorney-General Menachem Mazuz there was enough evidence to indict Mr Katsav over charges of rape, sexual harassment and wire-tapping.
The police investigation, initially overshadowed by Israel’s war in Lebanon, has brought Mr Katsav’s otherwise solid public career into disrepute as he fends off increasing calls for his resignation.
The previously low-key head of state and married father of five is Israel’s first president from an Islamic country and the first from a right-wing party.
The two-time cabinet minister who battled the odds to become Israel’s eighth president has repeatedly protested his innocence.
Born in Israel’s arch-enemy Iran and a fluent Persian speaker, Mr Katsav was elected by MPs in July 2000 as a relative outsider who upset frontrunner Shimon Peres, an ex-premier and Nobel peace laureate.
Considered a competent administrator within the conservative Likud party and as tourism and transport minister in the 1980s and 1990s, Mr Katsav emerged as a relative moderate since assuming his ceremonial position.
He offered to hold talks with Syrian President Bashar al-Assad and insisted the late Yasser Arafat had a role to play in the peace process at a time when the former Palestinian leader was spurned by then Likud prime minister Ariel Sharon.
Mr Katsav has used his presidency to play the protocol card abroad, making Israel’s “right to self-defence” during the second Palestinian uprising and warnings of rising anti-Semitism a constant theme of such trips.
He is a staunch defender of Israel’s controversial separation barrier in the West Bank, parts of which were denounced as illegal in a non-binding ruling from the UN International Court of Justice and slammed by the Palestinians as a land grab.
Mr Katsav was the first Israeli head of state to visit Austria, once annexed by Adolf Hilter as part of Nazi Germany, and Croatia, where an estimated 75 per cent of its 40,000 Jews were killed during the World War II Holocaust.
During a visit to Budapest in April 2004, police said they foiled an attempt to attack a Jewish museum, believed to be the Holocaust memorial that Mr Katsav was to open, but the prosecution later dismissed the charges.
At the funeral of Pope John Paul II in April 2005, Mr Katsav introduced himself to the president of Iran, who was born in the same town.
Mr Katsav said he shook Mohammad Khatami’s hand and spoke to him in Persian, also greeting Mr Assad during the traditional “exchange of peace”.
In February 2002, he invited Saudi Crown Prince Abdullah bin Abdul Aziz to come to Jerusalem to unveil an Arab peace initiative, or instead offered to visit him in Riyadh, although neither trip ever took place.
One of eight children, Mr Katsav was born in 1945 and arrived in Israel three years after the 1948 war of independence in what were difficult early years as a young immigrant in a fledgling Jewish state.
He lived in the modest Kiryat Malachi camp for new arrivals south of Tel Aviv, which later developed into a fully-fledged town, and became the first local resident to attend Israel’s Hebrew University.
In 1969, Kiryat Malachi residents elected the 24-year-old student as their mayor, Israel’s youngest. In 1977, he joined parliament and quickly entrenched himself in the hawkish Likud.
Studying economics and history, he taught to help support his family, before rising through the Likud ranks to serve as chairman of the Likud faction in the Knesset in the mid-1990s.
Married to wife Gila, Mr Katsav was Israel’s first president sworn in for a seven-year renewable term in the largely ceremonial post.