4 punctures in one week, even after replacing tube and tire, what's happening? I've just had my 4th puncture in 8 days on the bike I use to commute to work. Same back wheel each time. I haven't had a puncture before in the 2 years I've had this bike.

After the first puncture I replaced the tube.
After the second puncture I repaired the tube.
After the third puncture I replaced the tube and got a new tire.
Two days later it's punctured again.

What's strange is that the punctures - tiny, like a thin needle - have all been on the part of the tube facing the tire. They have all been randomly spread around the tube with respect  to the valve. Both these seem to indicate it has nothing to do with the rim, and yet with a new tire it's still punctured...?

Any thoughts?

(I'm considering the possibility that someone is sabataging my bike while it's parked in my university parking, though there is evidence against this also.)
The answer to my question -- why did my bike puncture four times, even after replacing the tube and tire -- turned out to be: bad luck. 

The first three punctures were caused by some damage in the tire (the punctures on the tube were all on the tire side). After I replaced the tire, I got another puncture - but this time the puncture was on the part of the tube facing the rim. On inspection I was that my rim tape was protruding up at the point of the puncture. Because I had a new tire and tube I had pumped the wheel up more than usual, which perhaps meant that rim tape protrusion was now a problem.

So, four punctures in one week: three from the tire, one from the rim.

For anyone else experiencing a confusing series of punctures, consider that you may be unlucky and that there are multiple problems in your wheel!