Freelance model Regina Soosalu's body was discovered on a beach on Rawa island off Malaysia's east coast last week.
She was initially believed to have drowned -- but police said they had found wounds on her body and were investigating the case as murder.
Hasnan Hassan, head of crime investigations in southern Johor state, told AFP seven people had been arrested so far for questioning over her death but declined to comment further.
Faris Waris of Tangerine Models said his agency had worked with Soosalu, who was in her 20s and had been in Malaysia on and off for about three years.
More From This Section
Her boyfriend, with whom she had travelled to the island, is a member of Johor royalty.
Violent crime against foreign tourists and expatriates is rare in Muslim-majority Malaysia, but the development comes amid two other high-profile crimes.
Police are investigating the death of a British tourist whose body was found last month on Tioman island, also off the country's east coast, after he went missing on a jungle hike.
And a Malaysian court today sentenced a shopkeeper to death for killing a French tourist also on Tioman in 2011.