Angel Lata Landi called his mother in Ecuador on Sunday, as he did every week. He told her he would not be able to send her money as he usually did because his bills had mounted. But he promised to make up for it soon.

The following day, in the next call she got from her family, his mother, Mercedes Landi, learned that her son was dead.

Mr. Lata Landi, a 36-year-old construction worker, was one of three people fatally stabbed by a man who went on a killing spree in Manhattan on Monday. Mr. Lata Landi was getting a ladder on West 19th Street when he was stabbed, his family said.

The assailant went on to kill two other strangers, the police said: Wilma Augustin, 36, a Haitian migrant who was living in a Midtown shelter; and Chang Wang, 67, who had been fishing along the East River. Ramon Rivera, 51, has been charged with three counts of first-degree murder in the attacks. He was arrested after a cabdriver saw the third attack, followed him and reported him to a police officer.

After attending Mr. Rivera’s arraignment in Manhattan Criminal Court on Tuesday, members of Mr. Lata Landi’s family said they felt hopeless, anguished and afraid.