SQL injection

Hi all, I saw some strange error messages from a site when I was surfing it, and it was in form of SQL. I did some testing of the security of the SQL injection protection of that site, and it showed it was not that protected against SQL injections. To show this to them, I deleted my own record in their database after finding out the table name of the "entity" in the database. I also found out a lot of other that I think is important table names. What I did to them was to report this to them, and inform them about the damage I created, and what could have been done. (I did DELETE FROM tablename WHERE id=1234, what if I did DELETE FROM tablename, destruction if no backup). This is a large "athletic site" in Sweden, with more then 100,000 daily visitors. What I am a little bit worried about is the legal part of this; can I be accused of breaking some laws? I was just doing it to check if they were protected, and I informed them about my process etc. I only deleted my record, no one else's. In Sweden it might have been called "computer break-in", but I am not sure. Anyone with experience of a similar thing? Best regards, Peter Lauri