Review of Death of an Expert Witness

I have been watching the Adam Dalgliesh mysteries from Netflix either by streaming (this one) or ordering the ones not streamed. I found Death of an Expert Witness quite confusing with respect to Dalgliesh's wife and child. A previous poster explained it somewhat, but I do wish the program had delved into it more. The wife and child died, but I was unsure in what way. Another poster said when she got into the taxi to go to the hospital it crashed killing them both. I have re-watched the first few episodes but no real explanation there. Then when Dalgliesh is in a church and the priest says he will miss the wife and will pray for the wife and child, I knew she died but not how. I am almost through with this program. I do like it, but I wish it had made the wife's death clearer.