A day later, on Long Island, the cruel symmetry of the tragedy was still too great for family, friends and officials to understand.
Evelyn Rodriguez, a wild baby of a mother who had gone to Washington and privately talked to President Trump about MS-13, the transnational gang that killed her daughter Kayla Cuevas and a friend, Nisa Mickens, in September 2016 with a machete Life to the memory of her daughter.
On Friday afternoon, two years almost to the date, she died fighting for her memory.
Ms. Rodriguez, 50, was run over by a car in Brentwood, Long Island, on the site of a memorial to her daughter, the police said. Ms. Rodriguez and Kayla's father, Freddy Cuevas, had argued with the driver about a shrine she had planted.
The police had not filed any charges on Saturday and would only say that an investigation was continuing. They definitely excluded any connection between MS-13 and the death of Ms. Rodriguez.
"It's beyond mourning," said Congressman Peter T. King, a Republican representing Brentwood, who had come into contact with Ms. Rodriguez. "I can not imagine a more horrible death for a child than being beaten to death and suffering a more terrible adult death than being crushed by a vehicle."
Barbara Medina, Mrs Rodriguez's closest friend, was not present when Ms Rodriguez was hit by the car, but she said she had spoken to Mr Cuevas, Ms Rodriguez's longtime partner, who reported on the events.
"They had set up a shrine for Kayla's second anniversary," said Ms. Medina. "When they came back, the shrine was gone, the balloon had burst, as was Kayla's picture, everything was gone."
Both Mrs. Rodriguez and Mr. Cuevas were on footage Recorded on Friday by News 12, a local TV station dedicated to the driver of a white S.U.V. – apparently over the broken shrine – about 90 minutes before the beginning of the memorial service. The police said the driver was related to a homeowner on the block.
As the video shows, Mr. Cuevas wagged his arms angrily and walked to the back of the vehicle while Mrs. Rodriguez stayed on the driver's side. It was then, according to Medina, that the driver accelerated.
"She beat her, hit her twice," said Mrs. Medina. "That was just useless."
The driver stayed to call 911, the police said.
The Suffolk County Police Department said on Friday that there had been a dispute over the placement of the monument, but did not want to comment on the specifics of the events.
"It has meant everything to me," Mr. Cuevas said in a brief interview in which he was heartbroken, just to praise Ms. Rodriguez's strength and encouragement.
On Thursday, a night's sleep was arranged in Brentwood at the same funeral home that Kayla had buried.
As tributes from Twitter, Governor Andrew M. Cuomo, and other leaders entered, it was clear that Ms. Rodriguez had united people in her life with her undeniable will. No mother, she said, should go through what she did.
Mrs. Rodriguez grew up in the Bronx and in Puerto Rico; Their public stance against illegal immigration was against criminals who came to the country and reported to schools.
"There was never any indication that she was making anyone politically responsible," Mr. King said.
Ms. Rodriguez focused her message on Mr. Trump to get more money for gypsy prevention programs and security measures there. She had sued the Brentwood School District for negligence in Kayla's death and her altercation with a member of the MS-13 gang, which the authorities said had started at school.
In May, she worked with Mr. King to have Mr. Trump appear at a round table in Long Island. She helped organize the presence of the undocumented family members of four young Latino men who were also killed by MS-13.
"I've never met anyone who had more courage and courage and never felt sorry for themselves," Mr. King said. "She never said," Why does this happen to me? "She always wanted to protect other people."
Mr. King said he was on his way to the vigil when he found out that she had died. When he got there, Mr. King said, streams of people were streaming down the street, unaware of what had happened. As the word spread, people's faces went blank, Mr. King said, "It was almost like, What will happen next to this community?"
Last summer, when Mrs. Rodriguez was preparing to meet President Trump for the first time in a speech to law enforcement officials on Long Island, she spoke of her activism.
Her words read like an epitaph.
"There are days when you feel that your world should end, just like your child's," said Ms. Rodriguez. "Then you realize that you have a new purpose: to fight, so that your child does not die in vain."