Prince Khaled al-Faisal "has submitted today the results of the investigation", the Saudi Press Agency said.
Faisal sent the findings to Crown Prince Mohammed bin Nayef for presentation to King Salman, it said, without disclosing any contents.
Salman vowed yesterday to reveal what caused the crane to topple into a courtyard of the Grand Mosque, where hundreds of thousands of Muslims have converged ahead of the hajj pilgrimage later this month.
Prince Faisal ordered a probe as soon as the tragedy struck.
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The investigative committee was headed by Hesham al-Faleh, an adviser to Prince Khaled, who was under orders to submit the findings urgently.
Nationalities of most of those killed have still not been revealed but they included Indians, Indonesians and a Thai.
Among the 238 injured were Iranians, Turks, Afghans, Egyptians and Pakistanis.
The crane which collapsed during a thunderstorm with extremely high winds was one of several working on a multi-billion-dollar expansion of the mosque to accommodate mounting numbers of faithful.