What a difference a comma makes

Here's a sentence for you:

Although Nina was released without charge by the police less than a week later she received a letter from a civil recovery firm demanding the princely sum of £137.50.

So, when was Nina released? And when did she receive the letter? Did she spend a week in jail?

Having checked, I have changed it to:

Although Nina was released without charge by the police later that day, less than a week later she received a letter from a civil recovery firm demanding the princely sum of £137.50.