• Elon Musk is trying to back out of his $44 billion deal to purchase Twitter.

• In his lawsuit against the company, he said it is undercounting the number of bots on the site.

• But Twitter's lawyers said the tool Musk is using once classified his account as a potential bot.

Elon Musk, the Tesla and SpaceX CEO who entered and soon tried to back out of a $44 million agreement to purchase Twitter, used an online tool to estimate the number of bots on the platform. But the service Musk used once labeled his own account as a bot, Twitter alleged in its rebuttal against him.

As The Washington Post noted on Friday, Twitter argued Musk used a public internet service called the "Botometer" to estimate the number of bots on the platform. Twitter's lawyers said the Botometer "earlier this year designated Musk himself as highly likely to be a bot."

The method Botometer uses to determine and estimate bots differs from the method used by Twitter, as the Post reported. Botometer, a project from the Observatory on Social Media at Indiana University, states on its website that it is a machine learning algorithm trained to calculate a score of how likely it is an account is a bot based on its Twitter activity.

Musk has cited the number of bots and spam accounts on Twitter as his primary reason for attempting to pull out of the deal, which he entered in April before quickly sowing doubt about the agreement and officially attempting to back out in July. Twitter sued Musk on July 12 over his attempt to exit the deal, and Musk countersued, arguing that the social-media giant lied to him.

Musk in his lawsuit argued that the company intentionally misled investors about the number of spam accounts and bots on the platform, as part of a "scheme to mislead investors about the company's prospects," as Insider previously reported.

Musk claimed that Twitter has 65 million fewer users than the company claimed, and said only 16 million people each day see advertisements on the platform. Twitter says it has about 238 million monetizable daily active users (mDAU), up 16% from the second quarter of last year. It maintains that just about 5% of accounts are bots.