Morning Briefing: Overnight Developments in the Orlando Nightclub Shooting

The shooting Sunday at the Pulse nightclub in Orlando left 50 people dead and 53 people hospitalized, making it the deadliest mass shooting in U.S. history.

Here are the latest updates related to the shooting, including news on victims, the gunman, reaction from around the nation. 

More details emerge about the gunman's movements before and during the slaughter: Authorities say the assailant arrived at the club Sunday just before 2 a.m.,  called 911 and reportedly pledged allegiance to the Islamic State. Soon after the shooting began, a police officer engaged the gunman, who briefly exited the club, then ran back inside and began claiming even more lives. Read more.

Authorities begin to release names of victims: About 14 hours after the mass shooting at the Pulse Orlando Night Club & Ultra Lounge, authorities began the slow task of releasing the names of victims whose families have been contacted. Authorities publicly identified additional victims overnight, but more than 24 hours after the shooting, the names of more than half of the victims have yet to be released. Read more.

The gunman had been on the FBI's radar, but investigators say they've found no direct links to terrorists: The gunman, identified as Omar Mateen, had been the subject of two terrorism-related investigations of by the FBI, both of which were closed for lack of evidence. Despite his claims of allegiance to ISIS, the FBI said he had no known ties to the group or direct ties to any other terrorist. Read more.

The gunman's father offers an alternative motive for the shooting, releases video: Seddique Mir Mateen, the father of Omar Mateen, the suspect in the attack on a nightclub in Orlando, Fla., posted a video on his Facebook page early Monday lamenting the death of his son and criticizing his actions. “I don’t know what caused this,” he said in Dari, as translated by The New York Times. “I did not know and did not understand that he has anger in his heart.” The father had earlier said that the shooting “has nothing to do with religion.” He said his son became angry when he saw two men engaged in a kiss in Miami a few months ago. Seddique said he believes that is what motivated the shooting. Read more.

Around the nation, people mourn, rally and vow to continue their lives unbowed: Following the lead of President Obama, many people around the country were angered by the attacks while demonstrating their sympathy for the victims. The President ordered flags flown at half-staff, people in Orlando lined up by the scores to donate blood and gay Pride celebrations around the country marched on. Read more.

The two presidential candidates weigh in; Trump tells president to step down: The two presumptive candidates in the 2016 presidential election wasted little time in releasing statements about the violence and how to prevent future deaths. Donald Trump took credit for being "right" about "radical Islam" and his plan to ban Muslims for entering the country, though the gunman was born in the United States. Hillary Clinton vowed to attack terrorists and tighten firearm restrictions. Read more.

Across the country, a possible separate attack on gay Pride averted: A 20-year-old man, who told police he was going to attend the Los Angeles Pride Festival, was arrested early Sunday morning in Santa Monica with assault weapons and explosives, authorities said. He has no known connection to the Orlando shooter, authorities said. Read more.