Complete with the present perfect or simple past form of the verbs. Mystery hacker strikes again A hacker(break) into the government's website and replaced all the photos with cartoon characters. The attack (happen) on Saturday night, and investigators believe that the same person(already / hack) into three other official networks. During Saturday night's attack the hacker (leave) a message to say that even a child could access the website. Investigators(not discover) anything about the hacker's identity since the attacks(begin).​

Mystery hacker strikes again A hacker BREAKS into the government's website and replaced all the photos with cartoon characters. The attack HAPPENED on Saturday night, and investigators believe that the same person ALREADY Hack.ED into three other official networks. During Saturday night's attack the hacker LEFT a message to say that even a child could access the website. investigators HAVE NOT DISCOVERED anything about the hacker's identity since the attacks BEGAN

Explanation:

The gaps has been properly filled with the adequate words in their grammatical form with the words in the brackets put in their present perfect or simple past form

all of the statements cuz