A lawmaker leading the Transportation Committee's investigation into the Registry of Motor Vehicles deepened his dispute with the Baker administration Tuesday, telling reporters he acquired documents that reveal a lack of transparency and greater knowledge than previously admitted about the RMV's struggles to suspend licenses before a fatal crash.

After speaking with the Boston Globe and WGBH over the weekend about his concerns, Rep. William Straus summoned reporters to his office Tuesday, where he distributed documents that he said were not provided by the Department of Transportation, but instead by an outside source.

Straus said the new documents hint that there was at least some correspondence within the RMV last summer — and with a top aide to Gov. Charlie Baker — that software installed in March 2018 struggled to prevent drivers with disqualifying histories from acquiring commercial licenses.

Another document, he said, shows that, in the wake of a crash allegedly caused by a West Springfield man whose commercial license should have been suspended, the same Baker aide declined to answer technical questions by email.

Straus stopped short of outright accusing the administration of obstructing the committee's investigation, but he said he is "trying to think of a benign reason" why the documents were not provided.

"In the absence of a benign reason, then I begin to think: was this intentional?" Straus told reporters.

None of the documents seemed to demonstrate prior knowlege outside of the RMV that out-of-state violations weren't being processed.

A Department of Transportation spokeswoman said the administration provided more than 970,000 pages of information to the committee after a "thorough search" to find any documents related to the committee's request. The department also provided 150,000 documents to national audit firm Grant Thornton, who conducted their own external investigation.

"MassDOT has not been contacted by the committee regarding this production and again has learned of this question through the media," spokeswoman Jacque Goddard said in a Tuesday statement. "MassDOT will continue to work with the committee on any requests to assist their investigation."

Three of the documents Straus provided to reporters Tuesday came from what he called "outside sources" and not from MassDOT.

One email in question was from Mindy d'Arbeloff, Gov. Charlie Baker's deputy chief of staff. On July 16, several weeks after the crash and after MassDOT had identified a significant backlog of unprocesses out-of-state violation notices, d'Arbeloff told MassDOT employees their technical questions about which codes should be entered as staff processed notices from out of state was "not an email conversation."

Instead, she said, a meeting would be scheduled where staff could discuss the topic.

Straus said earlier emails from that same thread were shared with the committee, but that the questions d'Arbeloff received and her response were omitted.

The chairman contested MassDOT's argument that all documents relevant to the committee's request had been produced, and argued that staff should have been communicating in writing about how to adjust RMV operations to clear a backlog of previously missed out-of-state violations.

"What was the motive, what was the reason to tell these people who were trying to fix a terrible public safety oversight within the Registry of Motor Vehicles?" Straus said. "The governor's office, or at least their representative, was telling these people, 'stop, we'll only talk about this, we won't write it down.'"

Another document Straus gave reporters is a July 2, 2018 correspondence, including "ATLAS release notes," written about four months after the new record-management software went online.

An attachment to the email, which was sent to dozens of MassDOT employees and to d'Arbeloff, describes an issue the software had suspending commercial driver's licenses, the type of license Volodymyr Zhukovskyy had — and should have had suspended — before allegedly killing seven motorcyclists in a crash this summer.

Straus said MassDOT provided the committee more than a dozen ATLAS release notes dated between April and August 2018, all sent from the same source and to the same distribution list, but the one describing commercial licenses was not included.

"Despite what's written as a conclusion or a summary in the Grant Thornton report that outside the Registry, people didn't know about this problem — this document shows they did," Straus said.

The chairman also pointed to a slideshow he did acquire from MassDOT, dated July 16, 2018, that includes language indicating software changes aimed at service center wait times were "prioritized" over other matters.

That, he said, is proof that the administration emphasized a "war on wait times" over back-end public safety issues, a charge Baker and others have denied.

Despite Straus's unusual step of calling reporters to his office Tuesday, the committee's next steps are not clear.

His co-chair, Sen. Joseph Boncore, did not participate in the press availability. Earlier in the day, when asked if he shared Straus's concerns, Boncore said he has been focused on "other priorities in the committee" and is still working through the RMV documents already provided.

Both chairs pledged to hold another oversight hearing to continue questioning witnesses, but Straus said Tuesday that was unlikely to occur in October as he continues to process previously unacquired materials.

He also declined to say whether the committee would now use subpoenas, an idea publicly floated after administration witnesses did not show up for the committee's first attempt to hold an oversight hearing.

"I expect that's one of the questions that leadership in both chambers will want to hear views on. I couldn't predict a conclusion on that," Straus said.