BOSTON — The number of drivers who saw licenses suspended in the wake of a Registry of Motor Vehicles scandal has doubled over the past month to more than 5,000 in a combination of old and new cases, officials said Monday.

Acting Registrar Jamey Tesler told the Department of Transportation's board that 5,260 Massachusetts residents have had their permission to drive revoked since July based on violations committed in other states.

A majority of those cases are based on past incidents previously missed by the RMV, which has been under fire for months because a driver who should have had his license suspended after an arrest in Connecticut allegedly killed seven motorcyclists in a crash.

In a mid-August status report, Tesler said the RMV's efforts to cross-check all 5.2 million Massachusetts drivers against a national database prompted suspensions for 869 drivers. Thousands of others were flagged for further manual review.

On Monday, he said the figure of suspensions from the National Driver Registry examination is now 1,869.

Suspensions from paper out-of-state notices also increased from about 1,600 in the August report to 3,391 as of Monday, although a MassDOT spokesman said the backlog had already been cleared and that the increase is attributed solely to new alerts that have come over in the normal course of business.

The response to the breakdown includes an outside review by national audit firm Grant Thornton and staffing expansions at the RMV, where a six-person team is being assembled to handle out-of-state notifications and new managers in safety roles.

"We are well underway to recruiting those positions," Tesler said. "We expect soon to be able to name the chief compliance officer and deputy registrar for safety."

Last month, the previously inactive Merit Rating Board that Tesler chairs fired Thomas Bowes, who had led the RMV's department of the same name that failed to process warnings from other states. Tesler then appointed Paolo Franzese to serve as interim MRB director for up to two months.

Grant Thornton already produced an interim report flagging several potential issues, including the fact that one employee viewed the Connecticut alert about Volodymyr Zhukovskyy, the driver who later allegedly caused the fatal crash, for seven seconds but did not act on it or alert any superiors.

Under the original agreement, Grant Thornton was expected to submit its final report this week, but Transportation Secretary Stephanie Pollack said Monday that both parties agreed to extend the review period by "several weeks" given the "voluminous amount of records and documents they had to review."

The Legislature's Joint Committee on Transportation is conducting its own investigation. Members have sparred with MassDOT officials for weeks over the degree of cooperation they met — they adjourned their first attempt at an oversight hearing after several key witnesses did not show up — and production of relevant documents.

On several occasions, committee chairs Rep. William Straus and Sen. Joseph Boncore hinted they may seek subpoena power to force compliance.

During Monday's meeting, Pollack said the administration has fully met the first request for materials lawmakers submitted and is working on the second one. About 512,000 pages of documents have been handed over so far, she said, and everything will be fully in the committee's hands by Sept. 25.

Massachusetts RMV officials have also re-established a secure file transfer process with New Hampshire, where the crash that prompted the scandal occurred, to ensure clear communication between the two states about driving violations, Tesler said Monday.

New Hampshire had its own backlog of unprocessed notifications and suspended more than 900 drivers as a result, though Gov. Chris Sununu said problems in the two states cannot be compared directly.

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