(CNN) Four weeks after a gunman entered Robb Elementary School in Uvalde, Texas, and killed 19 young students and two teachers, one of the state's top law enforcement officials offered a minute-by-minute breakdown of the police response -- and called it an "abject failure."
On Tuesday, Texas Department of Public Safety (DPS) Director Col. Steven McCraw shared a new timeline into the morning of the tragedy, one that offered new details from a previous breakdown he had shared with reporters.
"Three minutes after the subject entered the (school), there was a sufficient number of armed officers wearing body armor, to isolate, distract and neutralize the subject," McCraw told the Texas Senate Special Committee to Protect All Texans.
The only thing stopping those officers, McCraw said, was the on-scene commander who "decided to place the lives of officers before the lives of children." That commander was Uvalde school district police chief Pedro "Pete" Arredondo.
"One hour, 14 minutes, and eight seconds. That's how long the children waited and the teachers waited ... to be rescued," McCraw said.
This is the latest timeline from the director, detailing how the tragedy unfolded with the help of funeral home footage, school surveillance 911 and phone recordings and law enforcement body worn camera. (CNN has rounded the seconds in the timeline.)
At roughly 11:28 a.m. on May 24, the suspect crashes his grandmother's pickup truck in a ditch in front of the school and a funeral home, McCraw said. The 18-year-old gunman had been living with his grandparents, whose home was less than 0.3 miles from the elementary school, according to the director.
(Prior to that crash, the gunman was home and messaging a teen in Germany, CNN has previously reported. In those messages, he complained about his grandmother and at 11:21 a.m. texted: "I just shot my grandma in her head." Moments later, he said he was going to "shoot up" an elementary school.)
At about 11:29 a.m., two men from the funeral home go out to see the crash. Meanwhile, seconds later, a teacher who was inside the school calls 911 and reports a man with a gun, McCraw said.
At roughly 11:31 a.m., after firing at the men from the funeral home, the suspect begins shooting at the school from outside, McCraw said. The gunman fired 27 times while he was outside, shooting into classrooms, according to McCraw.
When the shooter reached the door he entered through, at the school's west entrance, it was unlocked, McCraw said.
(The door had been propped open by a teacher and later closed by the same teacher before the shooter entered, McCraw said. That educator was the one who called 911 about a man with a gun, McCraw said.)
A school resource officer who was not on campus but heard the 911 call drove to the area around that time and sped to the back of the school, to a person he thought was the suspect but was a teacher, McCraw said last month.
"In doing so, (the school resource officer) drove right by the suspect, who was hunkered down behind a vehicle, where he began shooting at the school," McCraw had said at the time.
At Tuesday's hearing, McCraw said that officer reported he was heading for the subject, which also caused confusion early in the police response.
At 11:33 a.m., the suspect enters the school, according to a timeline that accompanied McCraw's testimony.
The shooter begins walking and turns into a hallway that leads him to the adjoining classrooms 111 and 112. Roughly 30 seconds after entering the building, he begins firing into one of the two rooms, according to the timeline.
He pulls the door of one of the rooms open and walks in, McCraw said. According to the timeline, the shooter exited and re-entered one of the classrooms within moments.
Just before 11:36 a.m., three Uvalde Police Department officers with two rifles enter from the same door as the gunman, according to the timeline.
At 11:36 a.m., one officer with the Uvalde Consolidated Independent School District, as well as Arredondo, the district chief, and two Uvalde Police Department officers enter through another door of the school.
Three seconds later, three additional Uvalde Police Department officers and one district officer enter through the same door as the gunman, according to the timeline.
At 11:37 a.m., the suspect, from inside the classroom, shoots and injures officers approaching the classroom doors. Two of those officers received grazing wounds, McCraw said last month.
More than 100 rounds were fired between the time the shooter first attacked the classroom to when he shot at the officers, according to the timeline.
At roughly 11:38 a.m., an unknown officer says the subject was "contained in this office," according to the timeline, which cites body worn cameras. (This footage has not been released, but McCraw testified Tuesday his agency plans to eventually do so.)
That was not the right report for an active shooter, McCraw said.
At roughly 11:40 a.m., Arredondo, who did not have his police radio with him, called the Uvalde Police Department's landline, according to the timeline. (Earlier this month, Arredondo told The Texas Tribune he didn't consider himself the incident commander and left his police radio and campus radio outside the school because he thought carrying them would slow him down.)
McCraw shared a transcript of that landline conversation, during which Arredondo reportedly told the dispatcher the gunman had "shot a whole bunch of times," asked for the building to be surrounded and for more forces, saying, "We don't have enough firepower."
Moments later, the suspect fired one round, according to the timeline.
At roughly 11:41 a.m., a Uvalde police officer says, "We believe that he is barricaded in one of the offices," but adds, "there's still shooting," the timeline states, citing body camera footage.
A dispatcher asks if the door is locked. A police officer responds, "I am not sure but we have a hooligan to break it."
Shortly before 11:42 a.m., four first responders enter from a hallway. "Officers continue to flood into the particular area," McCraw said at Tuesday's hearing. Several moments later, a DPS trooper and two Uvalde police officers enter from the hallway.
At 11:44 a.m., the suspect fires another round. Shortly after that, a Uvalde police officer says, "Have some officers that are available to get everybody back," according to the timeline.
At roughly 11:48 a.m., school district police officer Ruben Ruiz -- whose wife, teacher Eva Mireles, was killed in the attack -- enters through the same building door as the gunman and is heard on body cam footage telling other officers, "She says she is shot," the timeline states.
"He got a call from his wife. His wife was in room 112," McCraw said Tuesday.
Local officials have previously said Mireles spent some of her final breaths on the phone with her husband, telling him she was dying.
Shortly before 11:51 a.m., an unknown officer says, "They need to get out of the hallway," according to the body cam footage. A Uvalde police officer says, "Chief is in there, Chief is in charge right now, hold on."
Moments later, seven border patrol agents enter through the same building door as the gunman. Nearly a minute after that, the first ballistic shield enters through that door, according to the timeline.
A Uvalde police officer is heard saying units were just "showing up," and asks, "Can you help with crowd control?"
"So officers after 11:52 are being diverted to crowd control activities," McCraw says.
At roughly 11:53 a.m., an unknown officer tells a DPS special agent all they need is a perimeter, according to the timeline.
Someone comments on whether there are still children inside. The DPS special agent responds, "If there is then they just need to go in," per the timeline.
Shortly after 11:54 a.m., a DPS special agent enters the school building and is directed to where the focus is, according to the timeline. He asks an officer, "Are kids still in there?" The officer responds, "It is unknown at this time."
A Uvalde police officer says the shooter is in classroom 111 or 112, adding, "Chief is making contact with him. No one has made contact with him."
Shortly after 11:56 a.m., an unknown officer asks if authorities don't know whether there are children inside. The DPS special agent says if there are, "We need to go in there." He repeats it a moment later. The unknown officer responds: "Whoever is in charge will determine that."
A police department channel recording says, "It is critical for everybody to let PD take point on this." An unknown officer asks where the gunman is, and another responds, "The school chief of police is in there with him."
Shortly after 11:58 a.m., the DPS special agent says the situation sounds like "a hostage rescue situation," adding, "they should probably go in," according to the timeline.
The agent then indicates he wants to clear more rooms in the school, according to the timeline. An unknown officer asks whether a supervisor should approve that. The special agent responds, "He's not my supervisor," according to the timeline.
Shortly after 12:03 p.m., a young girl from inside one of the adjoining classrooms calls 911, identifies herself and whispers the classroom she is in, McCraw previously said. The call lasted a minute and 23 seconds. She calls back several minutes later and says multiple people are dead.
"She's in room 112. And she was actually the only child in room 112 that was uninjured. There (were) eight children killed, two teachers killed in that room," McCraw said Tuesday.
Meanwhile, the second ballistic shield enters the building. Less than 30 seconds later, a third one enters, according to the timeline. "And yet, there's no action," McCraw says during the hearing.
At roughly 12:09 p.m., a Uvalde police officer is heard on body cam telling someone to "get the master key to the rooms."
Roughly a minute later, members of the Border Patrol's tactical unit, BORTAC, begin arriving at the school.
At 12:11 p.m., Arredondo now requests a master key. Roughly three minutes later, he instructs officers to have a sniper on the roof.
At 12:13 p.m., the girl calls 911 again, McCraw said previously.
A little after 12:15 p.m., a BORTAC member arrives inside the building.
Around 12:16 p.m., the girl calls 911 again and tells dispatchers there are eight to nine students alive, McCraw has said.
Around the same time, Arredondo is heard through body cam footage saying he needs a key. About a minute after that, he is heard telling people to wait, adding, "No one comes in," according to the body camera footage.
At 12:19 p.m., another person calls 911 from one of the adjoining classrooms and hangs up when another student tells her to, McCraw said last month.
Meanwhile, a fourth ballistic shield enters the building. The suspect then fires four rounds.
The timeline then quotes from body cam footage that offers a glimpse into Arredondo's actions in the minutes before the shooting:
Shortly after 12:21 p.m., he is heard asking for a breaching tool.
After 12:23 p.m., Arredondo says, "We've lost two kids. These walls are thin. If he starts shooting we're going to lose more kids. I hate to say we have put those to the side right now." He then tries to communicate with the suspect in English and Spanish.
"The entire communication was always one-way. The suspect never communicated, so it was not communication," McCraw said Tuesday.
At roughly 12:26 p.m., an officer says there's a teacher shot inside, and another officer responds, "I know."
At roughly 12:27 p.m., Arredondo is heard saying: "People are going to ask why we're taking so long. We're trying to preserve the rest of the life," according to the timeline.
Seconds later, he asks if there's a team ready and roughly a minute later, is heard saying he would get more keys to test on the door. Seconds later, he says the master keys are not working.
McCraw said Tuesday there was more than one master key for the classrooms in the school, which would explain why the one Arredondo had did not work.
At 12:30 p.m., Arredondo says authorities have cleared out everyone in the school except for the adjoining classrooms, according to the timeline. He adds they are ready to breach but that the room's door is locked.
More than three minutes later, he adds, "I say we breach through those windows and shoot his f**king head through the windows."
After 12:35 p.m., the Hooligan breaching tool enters the school. Meanwhile, Arredondo attempts to talk to the suspect again shortly after in both English and Spanish.
At 12:36 p.m., the student who initially called 911 calls again, is told to be very quiet and tells dispatchers, "He shot the door," McCraw previously said. She would later go on to ask dispatchers multiple times to send the police.
At approximately 12:41 p.m., Arredondo is heard saying authorities believe there are injuries in the room, according to the timeline. He adds shortly after that the rest of the building has been evacuated, so "we wouldn't have anymore besides what's already in there."
At roughly 12:42 p.m., the timeline states the district chief is again heard saying authorities are having trouble getting in the room because of the locked door. "He's got an AR-15 and he's shooting everywhere like crazy," he says, adding the gunman has stopped.
About a minute later, Arredondo says they need more keys. Three minutes later, he is heard telling others, "If y'all are ready to do it, you do it, but you should distract him out that window," according to the timeline.
Shortly before 12:48 p.m., a sledgehammer enters the building.
At 12:50:03 p.m., authorities enter the room and shoot and kill the gunman. Seven officers went in, with four going in first, followed by three more, McCraw said. Five officers fired at the subject, he added.