Russian authorities say two people from Moscow have confessed to a "ransomware" attack on a number of Apple device owners, mainly in Australia, last month.
A statement on the Russian Ministry of Internal Affairs website says that the duo, who live in the capital, hatched the scheme, which they carried out first by creating a "phishing" site to collect iCloud logins, and then locking the devices.
People in Australia woke up to find a message on their iPhone, iPad or Mac saying, "Device hacked by Oleg Pliss" and that to unlock it they should pay a ransom of US$100. Some users in New Zealand, the US and Britain were also affected.
The attack was carried out by using the "Find my iPhone/iPad/Mac" feature of the iCloud system. This lets users log in to any web browser and locate their devices if they are connected to the internet.
They can also make the device display a message, and lock it and, if they wish, wipe its data.
Apple had said only that the attack was not a break-in to its iCloud system, and that the affected users' login details must have been compromised elsewhere. It has not released figures on how many people were affected, though data from Australia and Apple's discussions boards seem to suggest that dozens were hit by it.
The two perpetrators - who were not named, but who were said to have been born in 1991 and 1998, which would make them about 23 and 16 - also confessed to another scheme, where they would connect a new device to a hijacked iCloud account, and then use it to acquire large amounts of media such as music and shows, which they then advertised for sale online.
One of those arrested had previously been tried on hacking charges, the ministry said.
During the raid on the hackers' apartments, police seized computers, sim cards and phones that they said were used for illegal activities, as well as "literature on hacking computer systems".
The Russian Ministry of the Interior Affairs said that there were different groups who were trying to carry out similar attacks.
Russia has been a centre for a number of criminal hackers, with organised crime sometimes involved in schemes to break computer security systems around banks and other high-profile organisations.