The new material sheds light on an incident in 2009 in which McNeil Consumer Healthcare, a unit of Johnson & Johnson, hired private companies to buy certain defective Motrin products from stores.

McNeil has said it did nothing wrong in removing the Motrin and that the medicine posed no safety risk. But investigators consider the documents significant because they deepen concerns about whether McNeil, responsible for a recall in April of an estimated 136 million bottles of pediatric medicines, was aboveboard in its handling of various quality-control problems.

Representative Edolphus Towns, a New York Democrat who is the chairman of the committee conducting the investigation, has suggested that the documents — which include e-mail messages, formal correspondence and instructions to contractors — raise the prospect that McNeil conducted a surreptitious Motrin recall in 2009 without the full knowledge of the Food and Drug Administration.

Mr. Towns, the chairman of the House Committee on Oversight and Government Reform, has repeatedly referred to the Motrin episode as a “phantom recall.”

One document on McNeil letterhead instructs contractors involved in the Motrin buyback program not to alert stores about their activities.

“Do not communicate to store personnel any information about this product,” the document says. A separate McNeil instruction said, “Just purchase all available product.”

Mr. Towns said that document, given to the committee by McNeil this week, indicated to him that McNeil had directed surreptitious activity by its contractors.

A McNeil spokeswoman, Bonnie Jacobs, disagreed.

“Given that there was no safety risk, the objective was to remove the affected product from a unique distribution channel, mainly convenience stores and gas stations, with as little disruption and consumer confusion as possible,” Ms. Jacobs said on Friday.

Earlier this week, Ms. Jacobs said that the company had nothing to do with a separate communication from a subcontractor hired to retrieve Motrin from stores.

In that document, also provided to the committee, the subcontractor instructed its employees how to behave — “Simply ‘act’ like a regular customer while making these purchases. There must be no mention of this being a recall of the product!” — when buying back the Motrin for McNeil.

On the issue of informing the F.D.A. about its activities, Ms. Jacobs said McNeil had contacted the agency after it discovered that two lots of Motrin did not dissolve properly. The company informed the agency that it planned to retrieve the products from stores and kept the agency apprised of its progress, she said.

An e-mail message from an F.D.A. official, obtained by The New York Times on Friday, suggests the agency was frustrated with McNeil’s approach.

“It seems that your company is doing a recall even though you are calling it a ‘retrieval,’ ” Neisa M. Alonso, an investigator and recall coordinator with the F.D.A. in San Juan, P.R., wrote in a message date July 16, 2009, to an executive at McNeil. “The agency’s position is that your company should do a voluntary recall of the product since it appears to be that you are already doing a recall of the product.”

McNeil later instituted a formal recall of the defective Motrin.