However, if witnesses do not testify voluntarily and summonses are issued by the commission to force individuals to testify, the report could be further delayed, the source said. The investigation into the shooting comes weeks after a gunman opened fire inside a classroom, killing 19 children and two teachers. The police reaction to the shooting has been strongly criticized after the tragedy, which is the second most deadly attack on a K-12 school in the United States. So far, members of the Texas Department of Public Safety, officers from the Uvalde Consolidated Independent School District, the Uvalde CISD inspector, Robb Elementary School principal, a teacher and security guard have been locked in for three days. This source says that the testimony went smoothly. It is unknown at this time what he will do after leaving the post. The list of witnesses for Monday’s hearing in Uvalde could be available early Monday morning and is expected to include members of the Uvalde City Police Department. The committee is scheduled to meet again in Austin on Tuesday. The three-member committee was formed by Texas House Speaker Dade Phelan earlier this month. Texas spokesman Dustin Burroughs has been named president, Joe Moody has been named vice president, and former Texas Supreme Court Justice Eva Guzman is a member. The preliminary report issued by the committee will be made available to the full legislature once completed, the source said. The purpose of this research committee is exploratory. There are two other committees of the Parliament, for Youth Health and Safety and Homeland Security and Public Safety, which are responsible for formulating legislative recommendations in the future. The first joint hearing by these two committees is scheduled for June 23 in Austin. CNN’s Holly Yan, Harmeet Kaur, Melissa Alonso, Amir Vera and Sharif Paget contributed to this report.