Oakland, California, May 14 (Reuters) - Elon Musk's lawyer questioned the credibility of OpenAI Chief Executive Sam Altman on Thursday as Musk's trial nears its end, in which he is seeking to persuade a jury to convict the chatbot company GBT and its board of directors of turning the nonprofit into a tool for personal gain.

Musk is suing OpenAI and its CEO, Altman, for breach of philanthropy and unlawful enrichment, accusing them of "stealing from a charity" by abandoning the company's founding mission of building safe artificial intelligence to serve humanity.

Musk said the defendants in the OpenAI case manipulated him into donating $38 million and then turned the tables behind his back by creating a for-profit business arm of the original nonprofit and accepting tens of billions of dollars from Microsoft and other investors to fund their expansion.

OpenAI says the organization is stronger as a for-profit entity, including the non-profit that is now a shareholder in the company, and that Musk was simply seeking to exert control.

In his closing arguments before the federal court in Oakland, California, Musk's lawyer, Steven Mollo, said that five witnesses, including Musk and former OpenAI board members, testified that Altman was a liar.

"Sam Altman's credibility is directly in question in this case," Mollo said.

Mullo added that Musk, in contrast, was committed to ensuring that individuals did not benefit from his money.

He continued, "Musk wanted OpenAI to remain a charitable project at its core. He did not want to shut down this non-profit organization."

The defense lawyers will present their closing arguments later on Thursday.

Musk is seeking approximately $150 billion in compensation from OpenAI and Microsoft, to be allocated to the non-profit organization OpenAI to support its humanitarian goals.

He also called for the dismissal of Altman and company president Greg Brockman. A Microsoft executive testified that the company had spent over $100 billion on its partnership with OpenAI.