Capabilities of digital forensics

CharacterInWhite said:

The first question is: Is it feasible for such a phone's SIM card to survive the detonation? We're not talking a high powered explosive either--the bomb in question is attached to an already weakened cable, and is there to give said cable a nudge in the right direciton, as it were.

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Perhaps, if the explosive were fairly weak, it could blow the sim card out of the phone and the chip would survive. The card would probably be ruined, but with the right tools you can still access the chip if it's intact.

Those things are unbelievably durable sometimes and fail if you breathe on them the wrong way other times.

CharacterInWhite said:

The second question is: If it is feasible, is it possible to recover partial data from a damaged SIM card?

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Not likely IMO. Those chips are so damn small, if it was physically damaged it would be useless, if not all the information would be intact.

AFAIK the only way there's ever partial information in computer memory is if it's erased, and scrubbed, but not 100% scrubbed clean.

If they're looking for the phone number that dialed in to the explosive device they could access that through the phone network.

CharacterInWhite said:

What I want to do is have them recover a partial phone number, which they can use to narrow down the search.

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Do you mean the phone number associated to the throw away phone or the number that called into the phone? Can a serial number on the phone lead them to original registration information that would include the phone number and call activity? I know SIMs can be moved between phones, but they all sell with an original SIM in them.

The phone could survive the blast physically in tact if it was thrown clear because it was somehow shielded from the actual blast itself (say explosive material was inside a 5 gal bucket and phone was taped to the lid that wasn't snapped on tight and the lid is thrown clear by the force of the blast) - it wouldn't be working, but it also wouldn't be in bits (or the bits could have logically been held together by duct tape on the lid).

How much time and effort are they willing to put into this?

First off, explosions are very unpredictable. Classic example is the Hitler assassinate attempt on 20 July 1944. An oak table leg, and an unplanned shifting of the bomb, and Hitler lived. So it's completely possible for the phone to survive the explosion.

What's less likely is for it to survive the burning car. Cars use a lot of plastics and other material that burn at a high temperature and rather thoroughly. Cars will frequently total themselves out between the time the fire starts and the fire department shows up.

But I've seen things survive fire that never should have, so it's definitely possible. And the melted down hulk of a cell phone is probable, and if found in an unusual area (like the engine compartment) would be investigated. And figuring out the car exploded is relatively simple. (Probably traces of nitrates will be around.) It's just not very probable. As a firefighter, I've seen quite a few burned out cars.

If the police have the resources, what they get is a search warrant for the nearest cell tower(s) for the time period of the explosion. The cell tower records all of the calls that travel through it (this is how the phone company creates billing records). You then start checking out the phone calls that happened during the appropriate time interval.

Once you find out the originator call, you get another search warrant for that phone's records. Which is why it will probably be a burn phone with only one call on it. But you'll find out what Wal-Mart it was sold from.

Best of luck,

Jim Clark-Dawe

Each cell phone has an MEID (smart phone) or EMIE (Basic cell) number on it. This number links the account (phone number) to a physical phone on the carriers network. If you get the carrier and this number you can get the call records from that carrier. This would lead you to the other phone number that called it.

Using an older style flip phone might allow you to get that number and say a plastic piece with a part of the brand. (example : Ver would most likely be Verizon)

Are you killing a person or a group of people? What kind of explosion do you want or need?