After visiting and questioning Mr. Cruz at his home in 2016, the Department of Children and Families determined he was not a risk to himself or others.
The informant made contact in the summer of 2016 with Trump campaign advisers who were already under scrutiny for ties to Russia.
A family friend who had taken in Mr. Cruz described her struggle over his behavior and guns before he moved out and was later accused of killing 17 people at his old high school.
Sheriff’s deputies stopped Zachary Cruz on Monday afternoon after he rode a skateboard onto the school’s property, the authorities said. School officials had told him to stay away.
The state attorney for Broward County said he would ask jurors to condemn Mr. Cruz to death after a rampage in Parkland, Fla., left 17 people dead.
The campus in Parkland, Fla., where 17 people were killed, reopened on Sunday for students and their families to retrieve belongings, reunite with friends and brace themselves for classes to resume.
The information should have been assessed and forwarded to the F.B.I. field office, the agency said.
Mr. Cruz, the suspect in the Parkland, Fla., school shooting, had no criminal history. But his childhood was certainly difficult.
Some of the 17 people who died in the shooting had tried to spare others during the chaos. Among the dead: a teacher, a coach, a dancer and a trombonist.
A commenter who shared a name with the suspect in the Florida school vowed to become a “professional school shooter” in a disturbing post that the authorities examined last fall.
Students at Marjory Stoneman Douglas High School in Parkland, Fla., remembered the suspect as a quiet student who nonetheless alarmed others.
Students at Marjory Stoneman Douglas High School in Parkland, Fla. hid in closets as a gunman fired a semiautomatic weapon into their classrooms. Seventeen people were killed.
This graduation season, The New York Times talked with seniors across the country who are not headed to college about their plans, hopes and dreams.
St. Andrew Catholic School, just outside Orlando, has embraced a state program that uses public money to allow low-income students to attend private schools.
Charles Kinsey, a behavior therapist, was shot by the police in North Miami, Fla., on Monday while trying to help a patient with autism. Mr. Kinsey was lying on the ground with his arms up when the police opened fire.
As the state prepares to vote on Tuesday, the candidates are at it again, circling and prodding each other in a final sprint before the high-profile contest.
Campaigning in Miami, he sounded a lot like the other Republican Cuban-American from the Senate whose presidential campaign he is looking to end.
Some American officials said that the Russians want help analyzing forensic evidence from the charter plane that broke apart over the Sinai Peninsula, killing 224 people.
The Texas senator, who is running for president, made the accusation against a fellow Republican amid a fight over the federal Export-Import Bank.
The investigation into the death of Jermaine McBean, who was photographed as he lay dying, was revealed in court records filed on Tuesday.