Elon Musk's Neuralink project is reportedly facing a federal investigation over employee complaints on animal testing, sources reported on Tuesday. 

According to relevant documents and sources, an estimated 1500 animals died as a result of lab experiments that kicked off in 2018. 

But the number of animals who die as a result of such experiments is not an indication of breaching federal laws. 

According to testimonies, mainly sourced from Neuralink's current and former employees, Musk's demands to speed research have caused a number of animal deaths beyond tolerable levels. 

According to regulatory filings, Neuralink ticks all of the USDA's requirements for safe and lawful operations.

Elon Musk said in April 2017 that Neuralink aims to make devices to treat serious brain diseases in the short term, aiming for human enhancement.

On December 1, Musk announced that the company's clinical trials in humans will likely begin within the next six months.

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