There were problems at Neuralink. Employees have said that Musk pushes for too ambitious goals. Musk's promises gloss over profound challenges standing in the way of a commercial brain implant for humans and downplays ethical questions that will emerge if it succeeds.

The venture is being criticized for how it is treating its animal test subjects. The US Department of Agriculture's Inspector General is investigating the wellbeing of animals at the company at the request of a federal prosecutor.

The news agency quotes interviews with many current and former employees of Neuralink at a time of growing employee dissent about Neuralink's animal testing.

According to the specific allegations, Neuralink has killed around 1,500 animals since the beginning of the year. It's not clear how many of the animals have died after being implanted with the prototype brain chip, which Musk said this week expects to be implanting in human subjects within six months.

Many mistakes endanger the wellbeing of animals, according to sources. The company allegedly bungled surgery on two pigs when it implanted their chips on the wrong vertebra, and the company's vet recommended killing one of the animals due to its poor psychological well-being.

Employees told the news agency that mistakes that led to the animals' deaths were often worsened by Musk pushing the company to work quicker than was safe. The company's work on animals was a "hack jobs" according to one employee. Several employees have left the company due to concerns about how the animals were being treated.

After Musk described the company's approach to surgery as "confirmatory, not exploratory", company researchers were told to scrub the word "exploratory" from study titles retroactively.

Neuralink's problems with perception of its testing had been going on for a while. A legal battle is underway to obtain photos of monkeys that were used in a Neuralink experiment.

A federal investigation, as well as what sounds like growing rancor at the company over Musk's dictatorial managerial style, could represent a dark shadow over the venture. The drama also comes at a time when Musk is facing a number of problems at his company.

A monkey can type with a brain implant, instead of using a typewriter.