CNBC has learned that Musk is in charge of the social networking site.
The Washington Post reported that the head of legal policy, trust, and safety was also dismissed.
If he didn't complete the acquisition by Friday, he would face a court battle.
Musk proposed buying the social media service and taking it private. Musk alleged that the company failed to adequately disclose the number of fake accounts on the service.
The lawsuit alleges that Musk refused to honor his obligations because the deal he signed no longer served his interests.
The two parties were scheduled to go to Delaware's Court of Chancery to determine the fate of the company and whether it would end up in Musk's hands.
In October, Musk changed his mind and said he would go ahead with his acquisition of the social messaging service if it dropped its litigation. The lawyers for the social media company said that the proposal from Musk was an invitation to further delay.
The judge in Delaware ruled that Musk had until October to make the deal or face trial.
Musk wrote a message to assure advertisers that social messaging services wouldn't become a free-for-all hellscape where anything can be said with no consequences.
Musk said in the message that it was important to the future of civilization to have a common digital town square where a wide range of beliefs can be debated in a healthy manner. There is a danger that social media will split into far-right and far left-wing echo chambers that will cause more hate and divide our society.
Musk arrived at theTwitter headquarters earlier this week carrying a sink, and documented the event on the social networking site.
Musk's description was changed to "chief twit".