WASHINGTON -- After initially rebuffing a House committee's demand for testimony on his decision to charge Boeing with an unfair-labor practice complaint, the top lawyer with the National Labor Relations Board (NLRB) has reluctantly agreed to appear at a congressional hearing Friday.

Lafe Solomon, the NLRB's acting general counsel, said he decided to do so only after the House Committee on Oversight and Government Reform made it clear it would "subpoena me if I do not voluntarily appear."

Solomon touched off furor in April when he alleged that Boeing built a second assembly line for its 787 jetliner in South Carolina as illegal punishment for strikes by Machinists union members in Washington state. Republicans quickly seized on the case as proof of organized labor's sway over the NLRB.

The Boeing case is being heard for the first time by an NLRB administrative-law judge in Seattle Tuesday. As the top prosecutor on the case, Solomon originally objected to having to testify before Congress, saying that it was improper and could interfere with a legal dispute.

But Rep. Darrell Issa, the committee's Republican chairman, rejected Solomon's offer to send a deputy in his place. In a letter to Issa, Solomon said he would appear if Issa insisted, but protested that none of his predecessors has ever been forced to testify about a pending NLRB case.

The AFL-CIO has called the hearing a "dangerous precedent" that threatens interference with an independent agency.

The June 17 hearing will be in North Charleston, S.C., the site of the new Boeing 787 Dreamliner assembly plant. Jeff Solsby, a spokesman for Issa, said the decision to hold the hearing away from Capitol Hill was not unusual and disagreed that Solomon's testimony could compromise the NLRB investigation.

Asked if the location of the hearing might appear prejudicial to Boeing workers in Washington, Solsby said it was part of the Republican Party's broad investigation into "impediments to job creation." So it makes sense, he said, to hold it in South Carolina "because that's where jobs will be created."

If Boeing is found at fault, Solomon has proposed the company be ordered to locate the second assembly line at its wide-body plant in Everett, regardless of what happens to the South Carolina plant.