I wasn't suggesting that Tabak was the culprit.
Just as well, that would be contempt of court.
I also don't know why some people think that anyone in their late 50s or early 60s would be incapable of doing this crime.
No one is saying otherwise.
The question is this; what is the average age of a murderer? I came across one source at HMP that said that the average age of a sexual murderer was 34. What would the life expectancy of a 34 year-old have been in 1974? 37 years perhaps? Which would mean that 50% of those that were 34 in 1974 would now be dead. Of those that were alive there would be a good chance that they were physically incapacitated in some way - disability is very much age related.
Now I don't really know the answers to any of those questions (but I expect an actuary would) but a back of the envelope calculation would suggest to me that it is unlikely that two murders in 1974 and 2010 were committed by the same person.