Perhaps no one could have predicted Ramon Rivera would allegedly go on a stabbing spree in broad daylight one month after getting out of jail, killing three people at random. But in the past, he had expressed homicidal thoughts and been hospitalized for serious mental illness, according to sources familiar with his case. Rivera’s mental health may have been involved in three tragic deaths, but it did not appear to play a major role in decisions throughout his criminal record. He had many arrests, mostly non-violent, including a burglary at a convenience store on Second Avenue. After ending up on Rikers Island in February, sources familiar with the case say some previous mental health issues resurfaced. Rivera was sent from Rikers to the Bellevue psychiatric unit at least twice. While there on May 6, he allegedly assaulted a correction officer. But court transcripts from a hearing three months later show no mention was made of the assault, nor Rivera’s mental health issues. He pleaded guilty in exchange for a 364-day sentence at that hearing. Had he served that full sentence, he would still have been at Rikers rather than on the streets of Manhattan Monday. Instead of remaining at Rikers until February 8, 2025, law enforcement sources say the city's Department of Correction used its "good behavior" standard to release Rivera on Oct. 17 after serving two-thirds of this sentence. Monday's attacks came just over a month later. Police said the first stabbing occurred at 8:22 a.m. on West 19th Street in Chelsea, when a 36-year-old man was knifed in the abdomen outside a construction site where the victim was working. He was pronounced dead at a hospital and later identified as Angel Lata Landi, of Peekskill. About two hours later, officers responding to a 911 call of a man stabbed on East 30th Street found a 67-year-old with multiple stab wounds to the abdomen. That victim, later identified as Chang Wang, also died at a hospital. Police said Wang had been fishing along the East River when he was attacked. Just 30 minutes after that came the third attack, a woman stabbed near 42nd Street and First Avenue. The 36-year-old, Wilma Augustin, of Manhattan, initially was taken to a hospital in critical condition with stab wounds to her chest and left arm. She later died of her injuries. Augustin was a migrant living in a midtown shelter with her young son, according to one of her neighbors. Rivera was apprehended a few blocks from that scene, found with blood on his clothes and the two kitchen knives, authorities said. A law enforcement source told NBC New York Rivera confessed to the stabbings, allegedly telling police he targeted victims who were alone and preoccupied at the time. Rivera was arraigned Tuesday and ordered held behind bars, with the judge noting his criminal history. His public defender asked for a mental health evaluation. His attorneys did not immediately respond to a request for comment. This story uses functionality that may not work in our app. Click here to open the story in your web browser.