Betty is a boy?

Ah no. I understood. Poor little friend of Betty. She's definitely a serial killer.

CK: ambiguous sentences are funny^^

Not only do I not believe this sentence is ambiguous, but also that Betty isn't a boy's name in any language. Besides, why would anybody use a foreign name in the original sentence? :p

Yes, this sentence isn't ambiguous, but the French translation (I just made a direct one from the indirect one) is.
The Frech one can either mean
"Betty killed her mother." (for example her own mother, or Maria's mother)
or
"Betty killed his mother." (for example Jack's mother)
So Betty doesn't need to be a boy to use "his" as "his" can refer to another person.

Already translated - see http://tatoeba.org/eng/sentences/show/377135

I am new to the site, so I assumed that when I didn't see a translation, there wasn't one. I have set things properly now, so it will show existing english translations.

This is a link you might find useful:
http://tatoeba.org/eng/sentence...eng/eng/page:1

It's a new feature so there's the odd glitch still there but it does the job.