What factors must be considered in determining if delay has violated the human rights of a person accused of sexual assault?

I am attracted by the approach of Powell, J., in Barker v. Wingo, supra, in identifying the factors to be assessed in determining if delay has violated a right of a person accused. Initially there is the length of the delay, and in the present case the delay has extended over a period of some five years. However, the length of the delay must be weighed against the complexity of the matter that was under investigation and the necessity to gather evidence from the extensive research of numerous documents and interviews with some 75 witnesses, 17 of whom reside in various countries in Europe.