Assesment of her lost electronics is imperative to understand whether if they can be traced through local networks and whether they present profitable targets for robbery. So far, and please do correct me if I'm wrong, we do know for sure she had an iPad which is missing and at least one other cell phone, which is (or are) also missing.
Now, this has been mentioned before, but every electronic device that are capable of connecting to mobile networks for data or voice transmissions have a unique IMEI number that's programmed into their chips at the production stage. Normally, this IMEI value is not supposed to be modified after production and any means to do that is strictly controlled by the manufacturer of the device. This is not to be mixed up with MAC ID numbers associated with wi-fi components of mobile devices. Tracing MAC ID numbers may or may not be feasible, I'll make another post for that possibility.
Focusing on her tablet and cell phone(s) is important as it is a promising lead which can make it clear if SS turned out to be murdered after an attempted robbery. Druggies or not, if her electronic devices were taken with the intent to profit off them, we can accurately predict where and how they might turn out.
Turkey has a centralized IMEI registry for preventation of mobile devices smuggled into the country being used, as importation of such devices are a good source of tax revenue. Mobile devices you can buy off the market and imported legally are already registered, as the distributors have legally imported them and paid taxes. However, any IMEI number that has not been recorded in the registry that pops up in any Turkish network is given around 30 days, in which the device can connect to mobile networks fully. It's a grace period mainly provided for the sake of convenience of tourists and travelers that spend a short period of time in the country. After this grace period, if unregistered, the device is added to the central blacklist and becomes incapable of connecting to Turkish operators' networks. Individual registration of the devices are only possible through a certain procedure. If you are a citizen, you need to claim to have bought the device abroad and brought the device to Turkey along with your luggage, provide your passport with stamps to prove that you have entered the country legally, which is then checked against border entry/departure records, which are again centralized. If you are a foreign permanent resident in Turkey, then you need to provide your residency permit/visa and you need to provide your passport to prove that you entered the country legally. Only after those documents and paying the registration fee/tax the device IMEI is whitelisted in the central registry.
Long term stays of the tourists are handled in the same way. You need to provide your tourist visa along with your passport.
However, in every scenario, you can only register a device every two years with a certain passport. Before the two year period is over, any following up attempts to register devices will be refused.
So, all this makes theft of mobile devices for resale in Turkey unattractive, as it will be blacklisted either through individual report of the theft or not being registered in the database. Thus, the prospect of stealing foreigners' devices for resale may not be considered attractive.
However, there are two more variables that must be considered. First, some mobile devices, depending on their make and model, are actually suspectible for IMEI modification, as their hardware is common enough to have been reverse engineered or the methods to modify those values were leaked from the manufacturer to the public. Second, even if we assume that IMEI modification is not possible, theft of mobile devices might still be considered profitable, as the device itself can be chopped off after the theft, and components can be individually sold with the exception of the motherboard, which has the IMEI programmed in, as spare parts. Or, they can be exported out of the country into any other country that does not have a whitelist based central IMEI registry. But such an operation needs to be organized, and if such operations do exist which export stolen devices are surely already have gone under LE scrutiny.
Now, we know that SS was seen in surveillance footage with what appears to be standard white Apple earbuds, listening to music on the go. It's reported widely and confirmed by the family that she had an iPad. However, carrying around an iPad to listen to music on the go is cumbersome, and I previously thought she most likely had an iPhone. There's no publicly available method to tamper any iPad model's IMEI number. Only Apple can do that. Same goes for every iPhone out there as well, except for iPhone 3G models with certain vulnurable outdated versions of the iOS installed, which provides a window of opportunity to not really modify the IMEI, but spoof it through software.
Considering there are photos of SS taken in a certain IG gathering some months ago in NY with a Samsung Galaxy SIII hanging out of her pocket, we can safely conclude that if she had a single cell phone, it was the Galaxy SIII. If she had two cell phones, at least one of them was that Galaxy SIII. (There might be an exception to that, I'll focus on it on the next paragraph)
Samsung Galaxy SIII comes in either an International variant, which I myself own that is marketed in EMEA and Europe mainly, or local country and network specific variants, which look exactly the same, but differ greatly with the internal hardware. International variant has the unique model code of GT-I9300.
GT-I9300 is not oficially marketed in the United States. It is either gray imported by trading companies or brought over from abroad by individuals. It's able to work on GSM networks, but not all CDMA networks, specifically Verizon and Sprint. Knowing that this was SS being abroad for the first time, I think we can dismiss SS having bought the SIII abroad quite safely. Any purchase from a gray import retailer would need upfront payment of the full device cost, which is around 700$ nowadays and considering SS family was not very well off, I don't think she'd have purchased it by paying upfront. We can assume she bought it through an operator contract through monthly payments.
I'm making this distinction, because we have a shot of understanding whether her device is suspectible for IMEI tampering and whether it was compatible with the Turkish networks, which are exclusively GSM. We don't have CDMA networks here and CDMA only devices cannot be used.
Here are the relevant variants of the Galaxy S3, with the added information whether they can operate on Turkish networks. I will research and add if they are suspectible to IMEI manipulation:
GT-I9300: International variant. Fully capable of operating in Turkish GSM networks. Suspectible to IMEI tampering. However, for the reasons I stated before, I don't think Sarai had this one.
SGH-T999[v]: North American variant. Mobilicity, T-Mobile, Wind and Videotron offer this variant through contracts. It's GSM capable and can work on Turkish operators. Suspectibility to IMEI tampering is currently unknown. Will be researched and updated.
SGH-I747[m]: North American variant. AT&T, Bell, Rogers, Telus, SaskTel and Virgin offers this through contracts. Fully GSM capable and can operate with Turkish networks. Suspectibility to IMEI tampering is currently unknown. Will be researched and updated.
SCH-R530: North American variant. Cricket Wireless, U.S. Cellular and MetroPCS offer it through contracts. Not GSM capable, cannot operate with Turkish networks. Therefore, suspectibility to IMEI tampering is completely irrelevant, unknown and will not be researched and added.
SCH-I535: North American variant. Exclusively offered by Verizon. CDMA only and lacks GSM compatibility, cannot operate in Turkish networks. Therefore suspectibility to IMEI tampering is completely irrelevant, unknown and will not be researched and added.
SPH-L710: North American variant. Exclusively offered by Sprint. CDMA only and lacks GSM compatibility, cannot operate in Turkish networks. Therefore suspectibility to IMEI tampering is completely irrelevant, unknown and will not be researched and added.
Americans, please do help me out here. Which of these operators mentioned above are prevalent in NY area? Perhaps some of you who might have contact with the family can inquest for relevant details? Can we know that she had a second mobile phone for certain, which she might have had before and brought over for GSM compatibility and operation in Turkey?
If we can be sure of the device variant, then we can look at robbery angle with more confidence (although all variants are indistinguishable from outside, we have a Skype connection made on 30th or 31st of January from either the iPad or cell phone(s), that's a promising lead) and we can certainly make good guesses about the prospects and possibility of tracing these devices.