Documents released Tuesday in a lawsuit against Monsanto raised new questions about the company’s efforts to influence the news media and scientific research and revealed internal debate over the safety of its highest-profile product, the weed killer Roundup.

The active ingredient in Roundup, glyphosate, is the most common weed killer in the world and is used by farmers on row crops and by home gardeners. While Roundup’s relative safety has been upheld by most regulators, a case in federal court in San Francisco continues to raise questions about the company’s practices and the product itself.

The documents underscore the lengths to which the agrochemical company goes to protect its image. Documents show that Henry I. Miller, an academic and a vocal proponent of genetically modified crops, asked Monsanto to draft an article for him that largely mirrored one that appeared under his name on Forbes’s website in 2015. Mr. Miller could not be reached for comment.

Mr. Miller’s 2015 article on Forbes’s website was an attack on the findings of the International Agency for Research on Cancer, a branch of the World Health Organization that had labeled glyphosate a probable carcinogen, a finding disputed by other regulatory bodies. In the email traffic, Monsanto asked Mr. Miller if he would be interested in writing an article on the topic, and he said, “I would be if I could start from a high-quality draft.”

The article appeared under Mr. Miller’s name, and with the assertion that “opinions expressed by Forbes Contributors are their own.” The magazine did not mention any involvement by Monsanto in preparing the article.

Mr. Miller did not respond to calls or a Twitter message asking for comment, and the Hoover Institution, where he is a fellow, could not reach him.

Forbes removed the story from its website on Wednesday and said that it ended its relationship with Mr. Miller amid the revelations.

Mr. Miller’s work has also appeared in the opinion pages of The New York Times.

“All contributors to Forbes.com sign a contract requiring them to disclose any potential conflicts of interest and only publish content that is their own original writing,” Mia Carbonell, a Forbes spokeswoman, said in a statement. “When it came to our attention that Mr. Miller violated these terms, we removed his blog from Forbes.com and ended our relationship with him.”

The documents also show that a debate outside Monsanto about the relative safety of glyphosate and Roundup, which contains other chemicals, was also taking place within the company.

In a 2002 email, a Monsanto executive said, “What I’ve been hearing from you is that this continues to be the case with these studies — Glyphosate is O.K. but the formulated product (and thus the surfactant) does the damage.”

In a 2003 email, a different Monsanto executive tells others, “You cannot say that Roundup is not a carcinogen … we have not done the necessary testing on the formulation to make that statement.”

The documents also show that A. Wallace Hayes, the former editor of a journal, Food and Chemical Toxicology, has had a contractual relationship with Monsanto. In 2013, while he was still editor, Mr. Hayes retracted a key study damaging to Monsanto that found that Roundup, and genetically modified corn, could cause cancer and early death in rats.

Mr. Hayes said in an interview that he had not been under contract with Monsanto at the time of the retraction and was paid only after he left the journal.

“Monsanto played no role whatsoever in the decision that was made to retract,” he said. “It was based on input that I got from some very well-respected people, and also my own evaluation.”