The union representing Capitol Police officers is rejecting an internal review of the department’s response to questions about September’s Navy Yard shooting as biased and inaccurate, but the Capitol Police Board is standing by its findings and Congress is unlikely to intervene at this point.

Labor Committee Chairman James Konczos, claiming the Capitol Police have a “culture of refusing to get involved in assisting the Washington, D.C., community,” is asking Congress to investigate why a highly trained team of four officers responding to the mass shooting on Sept. 16 was called back to protect the Capitol.

But House Republicans charged with oversight of the Capitol Police forces say they have no reason to question the work of a review team led by Assistant Senate Sergeant-at-Arms Michael Stenger that spent weeks interviewing dozens of personnel and others, reviewing written reports, radio transmissions and command center logs.

Stenger’s fact review team was established by the Capitol Police Board — Senate Sergeant-at-Arms Terrance Gainer, House Sergeant-at-Arms Paul Irving, Architect of the Capitol Stephen T. Ayers and Capitol Police Chief Kim Dine — at Dine’s request, in response to questions raised about the department’s response.

House Administration Chairwoman Candice S. Miller called the findings of the report “exhaustive” and “thorough,” and she praised the professionalism of the Containment and Emergency Response Team.

“You’ve got all of this traffic as far as what was on the radios and everything, so that it was very clear exactly how everything went,” the Michigan Republican told CQ Roll Call. “I don’t have any reason to question the investigation.“

In its two-page statement on the findings, the Capitol Police Board says the four-person CERT unit self-deployed to 11th and M streets Southeast and was then directed to head to the Navy Yard incident command post, but “traffic gridlock” prevented it from getting there.

The union disputes that claim, saying that the CERT officers arrived at the incident command post within minutes of the first call for assistance but relocated to ensure other first responders could reach the incident while they awaited further instructions from the Capitol Police.

The unit was recalled to the Capitol more than 30 minutes after reports of the attack.

“The facts are clear that the CERT was initially directed to the incident command post, and the facts are clear that they did not make it to the incident command post,” Irving said. “We also have radio transmissions from a Capitol Police unit at the command post that reflected they would be unable to make it due to heavy traffic congestion”

Konczos relies on initial reports from officers in the vicinity of Navy Yard, and reported by the BBC.

He also doubts the board’s ability to produce an unbiased report, since its members were responsible for high-level security decisions that day, including the decision to put parts of the Capitol on lockdown.

Gainer said Konczos has neither the facts nor the investigative experience to question the review and that the union chairman did not respond to “attempts by the chief of police to be briefed in depth on the review and its findings.”

The House Administration Committee has not announced plans to investigate police actions, but Konczos told CQ Roll Call he is “still working on that.”

Miller said she keeps in touch with the union but has not talked to it on this particular issue. She said she is certain to talk about the board’s report during an upcoming meeting with Dine.

“I keep a very open door and line of communication, whether it’s management or labor,” she said. “Each side has something to say certainly, and I want to hear it all.”

Rep. Robert A. Brady, D-Pa., ranking member on the House Administration Committee, did not have a comment for this story.

After reviewing the details of the board’s report, fellow House Administration Committee member Gregg Harper, R-Miss., found the investigation to be thorough.

“I’m satisfied that they did a really valid attempt to get to the bottom in the facts and the timeline,” he said.