Wouldn't that create a time paradox if you go back in time to solve unsolved crimes?
If I had a time machine. The first thing I would do is find out what happen to Jimmy Hoffia.
That would be a good mystery to solve.
How would it create a paradox if you went back, saw the crime as an observer took video evidence then shoot back to the current day and present your findings somehow.
There are a large number of unsolved kidnappings in Adelaide that would benefit from a time machine