A Texas House investigative committee is expected to release a preliminary report Sunday on the Uvalde, Texas, school massacre that left 21 people dead, more than a month after the group began its search for answers.

The report is expected to focus on the facts of the attack, include a chronological sequence of events, a timeline, a law enforcement manifest, and details on the shooter, a source previously told CNN. It is expected to clarify conflicting accounts of what happened, include verbatim quotes from sworn testimony, and show that the law enforcement failure that day was much greater than one person or one agency, one source has said.

Members of the Texas Department of Public Safety, the Uvalde Consolidated Independent School District police chief and officers, the district superintendent, the school’s principal, a teacher and custodial staff are among those who testified behind closed doors to the committee — with roughly 40 people testifying, according to one source.

Republican state Rep. Dustin Burrows, the committee chairman, said last month the group would do “everything in its power” to provide facts and answers about what happened “leading up to, during, and in the aftermath of this tragedy.”

Families of the victims are expected to receive the report and hallway surveillance video, with no audio, of the law enforcement response on Sunday morning to provide them with an opportunity to review it before meeting with members of the investigative committee.

Printed copies of the report were hand-delivered to Uvalde and Texas officials Saturday night out of fear the document might leak to the media before family members of the victims were able to read it, according to some of the officials who received the report.

The surveillance footage was leaked and published by the Austin American-Statesman newspaper on Tuesday, sparking outrage from both local officials and families who said they were blindsided and disrespected by the unexpected release.

In a statement after the video was published by the paper, Burrows said that while he was glad a portion of the video was made public, he was “also disappointed the victims’ families and the Uvalde community’s requests to watch the video first, and not have certain images and audio of the violence, were not achieved.”

The investigative committee’s report and the video are expected to be released to the public concurrent with Sunday’s meeting with family members. A news conference is scheduled for Sunday afternoon for members of the press to ask the committee questions.

CNN is reviewing the report now.