SAN DIEGO, Updated 11:34 p.m. PST January 25, 2001 -- An 18-year-old man was jailed Wednesday for allegedly engaging in sex with an underage girl moments before she mysteriously died outside the Mira Mesa Recreation Center.

San Diego homicide detectives arrested Sean Sebastian Smith on suspicion of having illegal intercourse with 14-year-old Nia Coleman, (pictured, left) whose sudden death Tuesday during an evening of partying with friends remains a mystery.

Emergency personnel, responding to a 911 call shortly before 6:30 p.m., discovered the dying girl on a discarded couch in a dark corner of a city park, according to San Diego police.

When the lifeless teen was found, her clothing was reportedly in disarray. According to police, it appeared as though the victim had been molested or raped.

Medics tried to revive the Mira Mesa teen, then took her to Children's Hospital, where she was pronounced dead a short time later.

An autopsy conducted Wednesday afternoon was inconclusive, San Diego Police Department Lt. Ray Sigwalt said. An official cause-of-death ruling is on hold pending toxicology tests, which are expected to take several weeks to complete.

What Led To Coleman's Death?

Witnesses told police that the girl had been drinking with friends at the park before going to a secluded area outside with a male acquaintance.

Investigators believe that Smith (pictured, right) was one of two young men hanging out and partying with the student and about six other juveniles over the day.

In addition to consuming "a considerable amount of alcohol," the group also may have been taking illegal drugs, the homicide lieutenant said.

Shortly before the girl's death, Coleman and Smith reportedly went off together to a secluded area of the park where several soiled couches sit shrouded by foliage and chain-link fencing.

"Most of the kids know that that's where to go to get some privacy," Sigwalt said.

Minutes later, Smith reportedly ran back to the gathering of youths, said that Nia was dead, and fled.

When medics arrived, someone was already administering CPR in a futile attempt to revive the girl. She apparently suffered the ailment or injury that killed her during "some type of sexual encounter," Sigwalt said.

Smith is facing charges for having sex with a minor. According to 10News, he could face more charges, depending on the results of the autopsy.

Community Mourns Loss, Asks Questions

Meanwhile, friends and classmates created a makeshift memorial at the park and have been paying tribute to Coleman with flowers, stuffed animals, balloons and cards.

Coleman's friends told 10News that she was a "happy person who would have done anything for anybody" and that they can't believe this happened.

Community members held a news conference Wednesday about teenage activity in the park. Many parents questioned why police did not do anything to stop illicit activity in the park.

Additional Resources:

• See Local School District Drug And Alcohol Study Results