Ricardo "Richard" Muñoz Ramirez (born February 29, 1960 in El Paso, Texas) is a convicted serial killer awaiting execution on California's death row at San Quentin State Prison. Prior to his capture, Ramirez was dubbed the "Night Stalker" by the news media.

Julian and Mercedes Ramirez had five children, the fifth being Richard Ramirez. The mother was a Catholic, and his father was a former policeman who later became a laborer on the Santa Fe railroad. Richard's father was also abusive and believed in corporal punishment.

Ramirez may have been influenced into killing by his cousin, Mike, a Special Forces Vietnam War veteran who boasted of killing and torturing his Vietnamese enemies and showed him Polaroid pictures of his victims. These included pictures of the severed heads of Vietnamese women, who in other pictures had been shown fellating Mike. Ramirez was present the night Mike shot and killed his wife, and her blood splattered on Ramirez's face. Ramirez was 13 years old at the time.

On March 17, 1985, Ramirez attacked 22-year old Angela Barrios outside her home. He shot her before entering her house. Inside was Dayle Okazaki, age 34, whom Ramirez immediately shot and killed. Barrios survived. The bullet had ricocheted off the keys she held in her hands, as she lifted them to protect herself. Within an hour of killing Okazaki, Ramirez struck again in Monterey Park. He jumped 30-year-old Tsai-Lian Yu and pulled her out of her car onto the road. He shot her several times and fled. A policeman found her still breathing, but she died before the ambulance arrived. The two attacks occurring on the same day bolstered media attention, and in turn caused panic and fear among the public. The news media dubbed the attacker, who was described as having long curly hair, bulging eyes and wide-spaced rotting teeth, "The Walk-in Killer" and "The Valley Intruder".