Yarddog, If you saw it on TV it must be true.
I read The Untouchables back in the early 60s when I was in high school and when the TV show was on. BTW, Robert Stack made a better Eliot Ness. Costner was OK tho.
The movie was not historically accurate except for bits and pieces. For instance they really did switch juries.
None of the Untouchables actually died.
The biggest thing they used to get info on not just Capone but members of his gang was through wire taps which were a fairly new tool at the time.