While it is possible to guess who down voted you, the guessing can only be reliable on low traffic sites. With the size of StackOverflow you simply cannot reliably guess - the user who decreased a point as your answer was down voted could have lost it by down voting something else entirely unrelated, and the person who down voted you may not have left an answer at all.
The fact that the suspected user gained a point when you deleted your answer may still have been coincidental - even if your guess is correct it isn't something that can be reliably guessed on the higher traffic sites.
However it is still a potential problem on lower traffic sites - at the very least the SE devs should look to implement this on the beta sites. There have been a number of times I have delayed answering or commenting on something so that my down vote could not be obviously linked back to me. There are scripts for auto reversal of serial down voting, but those are not going to pick up a few strategically placed revenge down votes.
as suggested by Martin in the comments, part of the solution can be to prevent users repeatedly deleting and undeleting answers, as this combined with relatively instant rep recalculations can be a dead giveaway. Either delay the rep gain caused by a delete (maybe have that adjusted daily), or introduce a delay between deleting and undeleting an answer.