Five months later, he participated in the last fight of his career, losing a close majority decision to the International Boxing Federation's champion, Robert Quiroga.
On February 28, 1992, Ruíz was ambushed and shot while traveling through one of San Juan's barrios, receiving six bullet wounds that fatally injured him.
On July 5, 1984, the pugilist signed his first professional contract, being managed by Lilliamery Valentín Conde, who presented the official documentation before the Puerto Rico Boxing Commission.
After more than five months of inactivity, Ruíz fought in his native Trujillo Alto, scoring the first knockout victory of his career over Marcos Claudio.
Ruíz the challenged then contender and former Continental Americas light flyweight champion, José "Cagüitas" de Jesús, losing a unanimous decision.
Consequently, Ruíz pursued legal advice before the Puerto Rico Boxing Commission, forcing the cancellation of his contract with Héctor Avilés.
[2] Ruíz began that year by fighting former World Boxing Council and Colombian flyweight champion, Prudencio Cardona, whom he defeated by knockout in nine rounds.
On April 29, 1989, Ruíz fought Sugar "Baby" Rojas to determine the first super flyweight champion of the newly created World Boxing Organization.
[4] Despite his opponent's experience advantage, Ruíz began the offensive by using his speed to land body punches, gaining control of the fight's tempo.
Ruíz was expected to be competing in bigger fights shortly, but a unanimous decision loss against José Quirino halted his progress.
Quiroga was originally scheduled to fight another Puerto Rican, Rafael "Baby" Cabán, who had to withdraw because of injury, opening the space to Ruíz.
[1] Domingo Álvarez, the coroner that attended the scene, noted that the pugilist's body displayed six bullets wounds that presumably caused his death instantly.
However, José "Toto" Peñagarícano, former president of the Puerto Rico Boxing Commission subsequently stated that Ruíz was murdered because he supposedly had a relationship with the girlfriend of an unidentified drug lord.
[2] On October 16, 1993, one year after his death, a massive boxing card was held by the Comité Pro-Familiares José "Cheíto" Ruíz (lit.
"Committee For the Wellbeing of José "Cheíto" Ruíz's Family") which featured the participation or support of seven Puerto Rican world champions.