Elon Musk's electric car company paid consultancy firm MWW PR to monitor its employees' Facebook activities during 2017 and 2018, when a union was formed in Tesla's Fremont factory, according to a report by CNBC.

Documents reviewed by the news outlet appear to confirm surveillance of employees online, which holds new relevance for observers seeking greater understanding of Musk's priorities where social media is concerned.

MWW PR kept a close eye on comments alleging unfair labor practices at Tesla as well as a sexual harassment complaint, CNBC says.

According to the records, Tesla paid MWW PR to monitor a Tesla employee Facebook group, to monitor Facebook more broadly for commentary on organizing efforts, and to conduct specific research on organizers, after which they developed labor communication plans, media lists, and pitches based on their reconnaissance.

Musk recently agreed to pay $44 billion for Twitter, the social network he has used for years to promote his enterprises and insult or disparage perceived opponents such as short-sellers, whistleblowers, the UAW, journalists, and Democratic Party elected officials. If the acquisition is completed, he is expected to become Twitter's interim CEO.

For years, union supporters have struggled with Tesla and Musk. Tesla fired a labor activist called Richard Ortiz in 2017 and Musk tweeted a statement that was later found to be illegal under federal labor regulations in 2018.

Tesla was ordered by the National Labor Relations Board to reinstate Ortiz and to have Musk erase his post, which they claimed jeopardized workers' compensation. Tesla has filed an appeal against the administrative court's decision, but his tweet has not been removed.

According to CNBC, Tesla's global communications director at the time, Dave Arnold, had ties to the PR and consulting business the manufacturer engaged to undertake this task. He worked as a vice president at MWW for roughly four years, from 2011 to 2015, after working as a communications director for former Rep. Anthony Weiner (D-NY), according to a news release from MWW announcing his hiring.

"MWW consulted with Tesla in 2017-2018 on a broad employee communications engagement during a period of rapid growth at the Company," a spokesperson for MWW PR told CNBC.

"It is a common practice to review media coverage and public social conversation about a company to gain insights into issues and perceptions of stakeholders about the brand."

Current and former Tesla employees who spoke with CNBC about the company's use of social media requested anonymity because they were not authorized to speak to the press or had signed non-disclosure agreements prohibiting them from making critical public statements about Tesla, according to the outlet.

Tesla is yet to comment on the matter.