Washington (CNN) How four US service members were killed in Niger -- and President Donald Trump's response to the attack -- has left the federal government searching for answers.

The Defense Department has opened an investigation to explain how about 50 ISIS-affiliated fighters were able to ambush a 12-man Green Beret-led team and why the team lacked sufficient support to ward off the attack.

The swirling story culminated in a remarkable moment for the Trump administration on Thursday: Chief of staff John Kelly, a retired four-star Marine general whose son was killed in Afghanistan in 2010, stepped into the White House press briefing room to defend his boss' handling of deaths in Niger.

Kelly described what happens to fallen soldiers and explained how the President came to tell a widow that her husband knew what he got into when he signed up to serve.

Kelly's remarks were the crescendo in an ongoing saga over the deaths in Niger. But it was the dozen days of silence from the President that has led to questions about the White House's attempts to handle the incident.

Trump first weighed in on the attack 12 days after the soldiers were ambushed, letting his spokespeople and the Defense Department take the lead.

The President, a very prolific Twitter user, never tweeted about the attack -- the deadliest US military exchange of his presidency. In the meantime, Trump used his preferred social media platform to lambast fellow Republicans, the NFL and the media.

And on Saturday, October 7, when the body of Sgt. La David T. Johnson was returned to the United States, the President was golfing

Here is a snapshot of what we know about the attack in Niger, the political fallout and Trump's actions over the last two weeks, drawn from public schedules, CNN's reporting at the time and interviews with a half-dozen administration officials:

October 4

The President visited Las Vegas where he toured a hospital, met with first responders and spoke with survivors of the deadly shooting that happened days earlier.

The news of the day was dominated by an NBC News report that Secretary of State Rex Tillerson called Trump a "moron" at a Pentagon meeting earlier in the summer. Trump slammed NBC for the report: "Wow, so many Fake News stories today. No matter what I do or say, they will not write or speak truth. The Fake News Media is out of control," he tweeted.

5:51 p.m. Initial reports of several servicemen killed in Niger.

Initial reports of several servicemen killed in Niger. 6:48 p.m. CNN's Barbara Starr reports US forces operating with Niger forces came under hostile fire in southwest Niger, according to US Africa Command.

CNN's Barbara Starr reports US forces operating with Niger forces came under hostile fire in southwest Niger, according to US Africa Command. 8:07 p.m. Trump, returning from Las Vegas on Air Force One, is briefed on the attack by chief of staff John Kelly.

October 5

The President spent most of the day behind closed doors. His only public event was memorable, though: During a photo op with military leaders and their spouses before a dinner at the White House, Trump said the photo represented "the calm before the storm."

7:36 a.m. US Africa Command releases a statement confirming "three (3) U.S. service members and one partner nation member were killed while the US was providing advice and assistance to Nigerien security force counter-terror operations, approximately 200 kilometers north of Niamey, in southwest Niger. Additionally, two US service members were injured and evacuated in stable condition to Landstuhl Regional Medical Center in Germany."

7:49 a.m. A US defense official tells CNN that "there are ongoing partnered operations in the area to locate those who conducted the attack on US and Nigerian forces."

A US defense official tells CNN that "there are ongoing partnered operations in the area to locate those who conducted the attack on US and Nigerian forces." 1:08 p.m. A US official tells CNN that the US forces in Niger were ambushed by up to 50 fighters likely affiliated with ISIS.

2:21 p.m. White House press secretary Sarah Sanders opens the White House press briefing with a statement on the soldiers in Niger, telling reporters that the White House's "thoughts and prayers are with the families and friends of the fallen service members who made the ultimate sacrifice in the defense of the freedoms we hold so dear."

7:29 p.m. Trump, during a photo op with military leaders and their spouses before a dinner at the White House, says the photo represented "the calm before the storm."

JUST WATCHED Brennan slams Trump's handling of Niger Replay More Videos ... MUST WATCH Brennan slams Trump's handling of Niger 02:20

October 6

Trump was entirely off Twitter on Friday. He received his presidential daily briefing in the morning, headlined a Hispanic Heritage Month event and signed a proclamation for National Manufacturing Day.

11:49 a.m. The Pentagon identifies three soldiers who were killed in Niger: Staff Sgt. Bryan C. Black of Washington state, Staff Sgt. Jeremiah W. Johnson of Ohio, and Staff Sgt. Dustin M. Wright of Georgia. Notably, they did not identify Sgt. La David T. Johnson of Florida, who had been unaccounted for.

The Pentagon identifies three soldiers who were killed in Niger: Staff Sgt. Bryan C. Black of Washington state, Staff Sgt. Jeremiah W. Johnson of Ohio, and Staff Sgt. Dustin M. Wright of Georgia. Notably, they did not identify Sgt. La David T. Johnson of Florida, who had been unaccounted for. 3:00 p.m. Multiple US officials tell CNN the body of a US service member who went missing following a deadly ambush Wednesday in southwest Niger has been recovered. The soldier was later identified as Johnson. The discovery of the missing US service member in a remote area of the northwestern African country by Nigerien troops came nearly 48 hours after he was first discovered to be missing in the wake of the attack.

Multiple US officials tell CNN the body of a US service member who went missing following a deadly ambush Wednesday in southwest Niger has been recovered. The soldier was later identified as Johnson. The discovery of the missing US service member in a remote area of the northwestern African country by Nigerien troops came nearly 48 hours after he was first discovered to be missing in the wake of the attack. 3:05 p.m. Sanders responds to a question at the White House briefing about why there had been no response from Trump to the soldiers killed in Niger. "I made a statement on behalf of the administration yesterday in the opening. Obviously, anytime one of the members of our great military are injured, wounded or killed in action, that is certainly something that we take very seriously. Our thoughts and prayers are with those individuals. We're continuing to review and look into this. And as we have more details, we'll certainly let you guys know."

Later in the briefing: Sanders is asked when the President was made aware that there was a fourth solider missing in action in Niger. She said that the notification happened on October 5, but could have to "get clarification on the specific timing of when that took place." Pressed, Sanders said that Kelly kept Trump "updated constantly on that situation as it evolved."

5:43 p.m. The White House announced that Trump spoke with French President Emmanuel Macron on topics including the fight against terrorism in Africa.

October 7

Trump went to his golf course. Reporters inquired about what the President was doing, but were not told. Later that night, he spoke at an Republican National Committee fundraiser in North Carolina. Upon leaving the White House, Trump spoke with reporters, commenting on Harvey Weinstein and North Korea. Trump tweeted on Saturday about his call on health care with Chuck Schumer, suggested that Republicans should get "equal time" on TV and said "only one thing will work" to combat North Korea.

1:42 p.m. The Defense Department identifies the fourth service member who died after a deadly ambush in Niger. Sgt. La David Johnson, 25, died as a result of enemy fire, the Pentagon said. His body was recovered by US personnel Friday, they announced. US officials told CNN that his body was recovered in a remote area of the northwestern African country by Nigerian troops and came nearly 48 hours after he was first discovered missing in the wake of the attack.

October 8

Trump slammed Senate Foreign Relations Chairman Bob Corker on Twitter. Trump also visited Trump National golf course in Virginia. Vice President Mike Pence left an Indianapolis Colts game after players on the opposing San Francisco 49ers knelt during the National Anthem. Trump later tweeted that he asked Pence to leave if players knelt during the anthem.

October 9

Trump tweeted his congratulations to Dallas Cowboys owner Jerry Jones for telling reporters that he would bench players that don't stand for the anthem. He also went to his Virginia golf club on Columbus Day to golf with Republican Sen. Lindsey Graham.

October 10

Trump met with former Secretary of State Henry Kissinger. The big meeting of the day was Trump's lunch with Tillerson, bringing the President in the room with a man whose intelligence he questioned in an interview. Trump was active on Twitter, questioning tax breaks the NFL gets, slamming an ESPN host and pushed back at sketchy reports that Kelly was going to resign.

Trump was also briefed by Defense Secretary Mattis and Joint Chiefs Chairman Joseph Dunford on options for North Korea.

JUST WATCHED McCain: Niger answers may require a subpoena Replay More Videos ... MUST WATCH McCain: Niger answers may require a subpoena 01:00

During the day: CNN reported the Green Beret-led team in Niger said that they had just completed a meeting with local leaders and were walking back to their unarmored pick-up trucks when they began taking fire from small arms, machine guns and rocket-propelled grenades. The new information comes from preliminary interviews that US military officials conducted with survivors of the firefight, information that was shared with CNN by a US defense official.

October 11

Trump welcomed Prime Minister Justin Trudeau and Mrs. Grégoire Trudeau of Canada. Trump said that they were going to discuss NAFTA and slammed another NBC report about him wanting to increase the US nuclear arsenal tenfold as "fake news." At night, Trump spoke about taxes in Harrisburg, Pennsylvania, and sat down for an interview with Fox News' Sean Hannity.

11:21 a.m. A US defense official tells CNN that the Pentagon plans to officially identify Wednesday the Islamic State in the Greater Sahel (aka Islamic State in the Greater Sahara) as the terror group responsible for the October 4 ambush. The group was identified based on intelligence gathered by the US military.

October 12

Trump issued an executive action on health care and tweeted that the federal government "cannot keep FEMA, the Military & the First Responders, who have been amazing (under the most difficult circumstances) in P.R. forever!"

The White House also announced on Thursday evening that the Trump administration will stop paying Obamacare subsides that help lower income people pay for health care through the program.

October 13

Trump delivered a red meat speech to the Values Voter Summit on Friday. He tweeted on his decision on the Iran agreement, his relationship with Pakistan and Obamacare.

October 14

Trump golfed -- again -- with Sen. Lindsey Graham. He tweeted his support for Virginia Gov. candidate Ed Gillespie, touted his own health care executive order and slammed health insurance companies. Trump later had dinner at the Trump International Hotel in Washington.

October 15

Trump went golfing with Sen. Rand Paul at his Virginia golf course.

October 16

JUST WATCHED Trump: Obama didn't call slain troops' families Replay More Videos ... MUST WATCH Trump: Obama didn't call slain troops' families 02:04

For the first time, Trump publicly commented on the Niger attack when asked about it by CNN's Sara Murray during a Rose Garden press availability with Senate Majority Leader Mitch McConnell. Trump also held a Cabinet meeting in the morning and traveled to Greer, South Carolina, for a fundraiser in the South Carolina governor's race.

2:06 p.m. "I felt very, very badly about that. I always feel badly. It is the toughest calls I have to make are the calls where this happens, soldiers are killed," Trump says. He claimed that past presidents -- including Barack Obama -- hadn't written or called the families of slain servicemen, though Obama spoke publicly during his term about his many interactions with the families of Americans killed in action. Later, Trump backtracked on the claim slightly, saying "I was told that he didn't often."

October 17

Trump met with Prime Minister Alexis Tsipras of Greece, and held a bilateral news conference with him. Trump also spoke about taxes during a Heritage Foundation event in Washington. On Twitter, Trump announced that Tom Marino was withdrawing his name as drug czar, blamed any increase in health care premiums on Democrats and touted his planned border wall.

9:56 a.m. Trump, in a radio interview, suggests reporters ask his chief of staff whether President Barack Obama called him after his son was killed in action. (Kelly's son, Robert, died when he stepped on a landmine in Afghanistan in 2010. Kelly, a retired four-star Marine general, was a lieutenant general at the time.)

Trump, in a radio interview, suggests reporters ask his chief of staff whether President Barack Obama called him after his son was killed in action. (Kelly's son, Robert, died when he stepped on a landmine in Afghanistan in 2010. Kelly, a retired four-star Marine general, was a lieutenant general at the time.) 12:05 p.m. The Defense Department announces they are conducting an initial review of the mission in Niger

The Defense Department announces they are conducting an initial review of the mission in Niger Afternoon: Johnson's body is returned home to Miami, with the plane receiving a water cannon salute as it arrived near the gate. The soldier's widow, Myeisha Johnson, emotionally drapes her body over the casket as one of her children stands next to her.

Johnson's body is returned home to Miami, with the plane receiving a water cannon salute as it arrived near the gate. The soldier's widow, Myeisha Johnson, emotionally drapes her body over the casket as one of her children stands next to her. 5:52 p.m. White House press secretary Sarah Sanders confirms Trump has called the families of the four soldiers killed in Niger.

White House press secretary Sarah Sanders confirms Trump has called the families of the four soldiers killed in Niger. Around 10 p.m. Florida Rep. Frederica Wilson tells CNN affiliate WPLG that Trump told Johnson's widow that the soldier "knew what he signed up for ... but I guess it still hurt." She said the call came shortly before Sgt. Johnson's casket arrived. (Wilson was in the car, listening on speakerphone along with Johnson's mother.) The White House declined to comment on Trump's conversation.

JUST WATCHED Tough questions remain about Niger ambush Replay More Videos ... MUST WATCH Tough questions remain about Niger ambush 04:07

October 18

7:25 a.m. Trump tweets that Wilson "totally fabricated" what he told Myeisha Johnson.

Trump tweets that Wilson "totally fabricated" what he told Myeisha Johnson. 10:30 a.m. Cowanda Jones-Johnson, who raised Johnson and also listened to the call, tells CNN Wilson's account of the call was "very accurate."

Cowanda Jones-Johnson, who raised Johnson and also listened to the call, tells CNN Wilson's account of the call was "very accurate." 2:57 p.m. Sanders, pressed on information about the attack and whether the President is satisfied with what is known about it, declines to get into the specifics of the raid. "I believe they are still looking into the details of that. But I don't think the President can ever be satisfied when there is a loss of life from men and women in uniform."

Sanders, pressed on information about the attack and whether the President is satisfied with what is known about it, declines to get into the specifics of the raid. "I believe they are still looking into the details of that. But I don't think the President can ever be satisfied when there is a loss of life from men and women in uniform." 3:07 p.m. CNN reports that a US private aviation contractor conducted evacuations of US & Nigerian troops after they were ambushed on October 4 in Niger, according to US Africa Command spokesperson Robyn Mack. The reporting raised questions about whether the French and contractor crews were in communication and certain they picked up all the personnel from the battlefield, given that Sgt LaDavid Johnson was left behind.

CNN reports that a US private aviation contractor conducted evacuations of US & Nigerian troops after they were ambushed on October 4 in Niger, according to US Africa Command spokesperson Robyn Mack. The reporting raised questions about whether the French and contractor crews were in communication and certain they picked up all the personnel from the battlefield, given that Sgt LaDavid Johnson was left behind. 3:12 p.m. Sanders defends the fact that it took nearly two weeks for Trump to comment on the attack, saying that is a "protocol" for when the President talks about a military operation.

Sanders defends the fact that it took nearly two weeks for Trump to comment on the attack, saying that is a "protocol" for when the President talks about a military operation. 3:32 p.m. Republican Sen. John McCain, chair of the Senate Armed Services Committee, tells reporters that he is asking for information about the Niger attack but isn't getting the answers he needs. Asked directly if the Trump administration is being up front about what happened, McCain said, "no."

Republican Sen. John McCain, chair of the Senate Armed Services Committee, tells reporters that he is asking for information about the Niger attack but isn't getting the answers he needs. Asked directly if the Trump administration is being up front about what happened, McCain said, "no." 3:47 p.m. Politico reports that a staffer at the National Security Council drafted a statement of condolence for Trump that was never released.

Politico reports that a staffer at the National Security Council drafted a statement of condolence for Trump that was never released. 5:56 p.m. A White House official tells CNN that the statement reported by Politico was crafted by the National Security Council, but when the White House press office received the information, staff decided it would be more powerful for Sanders to deliver this information from the podium in the briefing room

October 19