Skipper of speed boat results positive in toxicology test.

Italian authorities have opened an investigation into the death of a 45-year-old American tourist who was killed after the chartered motorboat she was travelling in crashed into a sailing ship off the southern Amalfi coast on Thursday.

The woman has been named by Italian media as Adrienne Vaughan, the president of the publishing house Bloomsbury USA, best known for publishing the Harry Potter books.

The motorboat collided violently with the 45-metre yacht, which was carrying a wedding party of around German and American tourists, near the Fiordo di Furore.

The impact threw Vaughan over board where she suffered fatal injuries from the boat's propellers. 

The 30-year-old skipper of the motorboat, who was injured in the crash, failed toxicology tests, according to Italian news reports.

Vaughan had been visiting Italy on a family vacation with her husband, who was taken to Ravello hospital with limb injuries, and her two children, aged 12 and eight, who are being treated for shock.