Europol, the European Union's police agency, sent a team of organized crime experts to help Maltese police investigate the assassination, joining the FBI and Dutch forensic experts.
Just before her death, Caruana Galizia, 53, had posted on her closely followed blog, Running Commentary, that there were "crooks everywhere" in Malta. The island nation has a reputation as a tax haven in the European Union and has attracted companies and money from outside Europe.
The journalist focused her reporting for years on investigating political corruption and scandals, and reported on Maltese mobsters and drug trafficking. She also wrote about Maltese links to the so-called Panama Papers leaks about offshore financial havens.
Caruana Galizia had also accused senior figures in government and opposition of corruption and money laundering. They have all denied the allegations and Galizia was hit with 36 libel suits in the nine months preceding her death.