When Did Shapeshifter Die?

In The Benders, it was revealed that the Shapeshifter was killed on March 7, 2006.

Did Shapeshifter die?

Dean arrives and shoots the shapeshifter twice in the heart with silver bullets, killing it. As the shapeshifter was caught in the act of trying to kill Rebecca in Dean's form, Dean is blamed and Zach and Alex are released. The shapeshifter is buried as Dean Winchester, allowing Dean to fake his death.

How do shapeshifters die?

Decapitation – Like most things, a shifter can be killed by cutting off it's head. Iridium – The rare metal iridium was shown to be the only thing capable of injuring the Alpha Shapeshifter. Crowley discovered this while experimenting on other shifters.