Who was the second European to reach Timbuktu in 1828 and the first who returned alive?

A British officer, Major Gordon Laing, was the first European to reach Timbuktu in 1826 but was murdered in September when leaving the city.
René Caillié, 1799-1838, a French sailor, learned that the Geographical Society of Paris was offering a prize of 10,000 francs to the first European who reached the city of Timbuktu and lived to describe it. Travelling in the hold of a ship he shared with slaves, he arrived in Timbuktu on 20 April 1828. Disguised as a poor Egyptian (he had spent a year learning the Arabic language and Islamic culture) trying to reach Cairo after years of living in France, he spent two weeks in the city, taking notes and making drawings surreptitiously. he found a way out of the city when he joined a slave caravan travelling across the Sahara and the Atlas Mountains, eventually reaching Rabat in Morocco without money and poor health, dressed in rags but was refused aid. He trekked northeast to Tangier where was able to meet the French consul and obtained passage back to France where he claimed his prize and was given a pension. However, he had contracted TB in Africa and died prematurely in 1838.

https://static-prod.lib.princeton.edu/visual_materials/maps/websites/africa/caillie/caillie.html#:~:text=He%20arrived%20in%20Timbuktu%20on,other%20terrain%20unknown%20to%20Europeans.