As congressional leaders and the Obama administration were moving to enact gun control measures in the wake of last week’s massacre at Sandy Hook Elementary School in Newtown, Conn., Connecticut State Police officials said Thursday that it will probably be weeks before authorities release additional information about the motive of the shooter.

Lt. J. Paul Vance, a state police spokesman, said investigators are piecing together leads but have failed to uncover what triggered Adam Lanza’s rampage six days ago.

“We don’t have any smoking gun to say this is why it occurred, at least not yet,” Vance said. “We are moving forward and working with our partners, and as you can assume with multiple deaths, we are looking at several months before we really have our arms wrapped around this.”

U.S. Attorney General Eric H. Holder Jr. was traveling to Newtown on Thursday to meet with law enforcement officials and investigators, the Justice Department announced. There were to be no public events, and Holder was not expected to speak to the media.

Holder was planning to travel to Newtown after meeting at the White House with Vice President Biden, who is leading the administration’s efforts to deal with gun violence.

House Speaker John A. Boehner (R-Ohio) promised Thursday to “take under advisement” any suggestions to curb gun violence put forward by the Biden commission.

And while he did not commit to allowing votes on any new gun control measures, he did not reject out of hand a discussion of such ideas.

“When the vice president’s recommendations come forward, we’ll certainly take them into consideration,” Boehner told reporters. “At this point, our hearts and souls ought to be thinking about those victims” of the school shooting.

The Hartford Courant reported Thursday that investigators were having difficulty retrieving information from Lanza’s computer because he smashed his hard drive before he went to the school. The newspaper also reported that investigators have discovered that Lanza made few calls from his cellphone in the weeks leading up to the incident.

But Vance said investigators remain optimistic that they can recover clues from his damaged hard drive.

“State police have a very comprehensive crime laboratory, and the FBI has the same capability,” Vance said. “Any electronic equipment that was seized is going to be examined, and we are certainly believing there is information that is going to be helpful to us in this case.”

Vance said investigators are sorting through numerous pieces of evidence recovered from the Lanza family home.

“We spent countless hours going through every stitch of that house we could uncover,” Vance said.

Although he declined to comment on reports that police took numerous video games from the house, Vance said, “all electronics” are in police custody.

Vance said it is still unclear how many rounds were fired in the shooting, except to say it was “a substantial” number.

No formal media updates are expected “for several weeks,” Vance said, and investigators will work through the holidays “dissecting the shooter from the day he was born to the day he died.”

Rep. Joe Courtney (D-Conn.) said “the hunger for information” about the Lanza family and Adam Lanza’s motive is “overwhelming” around the state.

But Courtney, a former public defender who represents eastern Connecticut, said elected officials and residents remain confident that police and federal officials are working as fast as they can, “given the fact some of the key witnesses lost their lives.”

“I have some understanding how difficult it is to piece something like this together,” Courtney said. “They want to be careful about not making bad conclusions. . . . This is about as large as it gets, so I still give them some slack and time.”

When asked whether it was possible that Lanza’s motive would never be known, Vance said “that is always a possibility in a case like this.”

“But the magnitude of this,” Vance added, “and all the resources we are directing at this . . . if there is an opportunity to uncover a motive, we will definitely uncover it.”

Rosalind S. Helderman and Rachel Weiner contributed to this report.