Hello Peter, Pity little detail was available on the DC, it is however quite common on deaths such as his.
Sometimes all that authorities have to go on is what is found as personal effects in the deceased abode. Advertising is done, but if no one is looking then that's it.
Tusculum Street is actually in Potts Point an adjoining suburb to Kings Cross, I drove up it only a few weeks back while in Sydney. I worked all over that area in the 1970's and it was a much busier place then. The street has undergone some redevelopment in the past 40 years from what was nearly all blocks of flats, common brownstone type. Not completely seedy, but was the haunt of some of the more colorful types of "The Cross". It was handy, as it was a short walk up the hill to the well lit cross. I just had a look on Google maps for 26 and it doesn't seem to be there so could have been redeveloped. The street is a dead end "Cul de Sac" and used to be on two levels which has nearly disappeared into just a dividing streets-cape
I knew a few people who lived in that type of flat in those streets in the 1970's which are pre WW2 and lack modern convenience. They were mostly 4-5 floors and built on the street edge comfortable but not flash. Unfortunately because of the types that lived there during the late 60's - 1970's there were a few murders took place. Much quieter now.
Neil