Two days ago Gee tweeted that she had met former US President Bill Clinton, who visited Zanzibar on Monday to pledge support for anti-malaria work through his Clinton Health Access Initiative.
Bashir Ismail, of Art in Tanzania, said they had argued with a nearby shop owner a few days ago when they went for groceries.
Ismail said the two women, who were staying in Stone Town, were properly dressed when the attack happened as they were going for dinner at a beach restaurant.
"The two attackers passed by several white tourists in the area and threw acid after reaching closer to them which raises suspicion of a planned attack," Ismail said.
A friend said Katie, a former pupil at Francis Holland School in Sloane Square, Chelsea, had also been attacked two weeks ago.
Oli Cohen, 21, said: "The girls were walking through the town singing on Ramadan when a Muslim lady came up to her shouting. She lost her temper and reacted violently - and hit her in the face for singing.
"I don't know what song it was but it wouldn't have been anything excessively aggressive or rude - they're so well-mannered and respectful they had gone to the town to do voluntary charity work.
"It was an isolated incident and I don't believe it had any connection, she didn't suffer any serious injuries - but they were both extremely shaken up by it. Not enough to come home but I know they felt uneasy being in public. Some people would stare or say things to them.
"I think white good-looking north London Jewish girls walking around in Zanzibar always make them a target as it's a Muslim country."
The friends were in the final week of their trip on the island, a popular tourist destination famous for its white-sand beaches and spice plantations, when the attack happened in Stone Town, the island's capital, on Thursday.
Two men on a moped drove past the pair and the pillion passenger threw the liquid at them before speeding off.
Speaking for the first time since the attack, Katie's mother Nicky Gee said: "I've spoken to my daughter - her whole face and body is burned.
"It was an acid attack on two English girls. They were dressed appropriately - they just attacked two young girls."
The teenagers both suffered injuries to their faces, chests and hands, and were transferred to a hospital on the Tanzanian mainland.
Jakaya Kikwete, Tanzania's President, visited them at the Aga Khan Hospital in Dar es Salaam and promised that their attackers would be found.
"It's a shameful attack that tarnishes the image of our country, I order security agents to speed up the investigations and arrest the suspects," he said.
Tanzanian police want to question an Islamist preacher to question him about the acid attack, a senior officer said.
Sheikh Issa Ponda Issa heads the Council of the Islamic Organisation, a radical Muslim outfit based in Dar es Salaam, and was found guilty in May of breaking and entering linked to riots that followed reports of a Christian boy desecrating a copy of the Koran.
He was given a 12-month suspended sentence.
Issa spent a week in Zanzibar at the beginning of August, preaching in mosques and advocating his supporters to demonstrate "like in Egypt" in order to secure the release of 10 imprisoned members of an Islamic separatist group.
There had been talk in Zanzibar that a group called Uamsho, or The Awakening in Swahili, were planning public protests or some kind of action to coincide with the end of Ramadan.
Uamsho wants Zanzibar to split from the Tanzanian mainland, which it blames for bringing alcohol and Western ways to the islands.
The Sheikh visited imprisoned Uamsho members in jail while he was in Zanzibar, the officer confirmed.
