Minerliz Soriano; Joseph Martinez aka Jupiter Joe

The 13-year-old was a straight-A student who wrote poetry in her journal about love and rainbows. She dreamed of one day becoming an astronaut.

“I used to make fun of her about it,” says her best friend Kimberly Ortiz. “I used to tell her, ‘We’re from the Bronx, we’re not going to be astronauts.'”

Joseph Martinez.Luiz C. Ribeiro

Joseph Martinez

Four days later, her strangled body was found inside a dumpster behind a Bronx video store, about two miles from her home. There were signs of sexual abuse.

“I carried a lot of guilt with me for years,” says Ortiz about not walking home with her friend. “I made a promise to her in front of her casket that I would figure out who did this to her.”

On Nov. 30, after 22 years, authorities finally made good on Ortiz’s promise, announcing they had charged Minerliz’s neighbor Joe Martinez with two counts of murder.

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Martinez has pleaded not guilty, and his lawyer, Troy A. Smith, says the murder charge “doesn’t make sense,” adding that his client “maintains his innocence.”

Courtesy Kimberly Ortiz

Kimberly Ortiz

The arrest is bittersweet for Minerliz’s aunt, Amelia Soriano, who always believed the girl’s murder would one day be solved.

“I felt that it would come to light,” she tells PEOPLE. “It was very sad not knowing, no one seeing anything, no one knowing anything. He threw her in the dumpster like she was garbage.”

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But he was never considered a suspect, and the case went cold. Two decades later, however, when DNA found on Minerliz’s sweater partially matched that of Martinez’s deceased father, investigators collected discarded DNA evidence from Martinez — which they say was an exact match.

“When we have a success like this, it’s a great thing,” says retired NYPD homicide detective Malcolm Reiman, who worked on Minerliz’s case. “Homicide cases have a ripple effect, so you are not only working for the dead victim but the other people surrounding that victim as well.”

The charges against Martinez have come as a shock to those who knew him.

“I’m still thinking there’s got to be a mistake,” says Joe Alcott, who met Martinez at a robotics conference, where Martinez gave a lecture. Alcott says Martinez seemed like “a fantastic guy.”

Meanwhile, Minerliz’s aunt Amelia can’t help but wonder what life could have been like for the bright, promising teen.

“She was very caring, a lovely, loving girl,” she says. “Who knows who she could have been, or what she could have done?”

source: people.com