Location of Jesus' tomb identified by Helena, mother of Constantine?

I was reading a National Geographic article about the recent restoration work done at the Church of the Holy Sepulchre in Israel in which the stone slab that covered the supposed resting place of Jesus was removed. According to the article, it went on to say: > ...it was first identified by Helena, mother of the Roman emperor Constantine, in A.D. 326. I researched a bit more about Helena's visit to Jerusalem and came upon another article that had this to say about her visit: > The site was identified in the year 326, when the Emperor Constantine’s mother Helena went on a pilgrimage to the Holy Land in search of relics from the time of Christ. She asked the residents of Jerusalem where the site of Jesus’ tomb was, and they directed her to a spot where a pagan temple now stood. We might be justifiably sceptical that the people in Jerusalem at that time would have known where Jesus’ tomb once was and suspect that out of deference to the Emperor’s mother they pointed to some site. Read more: [#500 Excavating the Tomb of Jesus](http://www.reasonablefaith.org/excavating-the-tomb-of-jesus#ixzz4QDzpfrWk) **Does anyone know the source for this claim? Specifically want to research more on Helena asking residents of Jerusalem where the site of the tomb was.**