Teresa was last seen inside her family's apartment in the in the 8100 block of Marquette Avenue Northeast in Albuquerque, New Mexico during the evening hours of July 1, 1998. Her mother said that Teresa took a plate of fries and a soda into her bedroom at approximately 11:00 p.m. Teresa's mother awoke at approximately 3:00 a.m. on July 2 and noticed that her daughter's bedroom door was swinging open in the breeze. Teresa's television and stereo were turned on, but there was no sign of her inside the apartment. All of her personal belongings had been left behind, including her money, purse, watch, jewelry, cosmetics and prescriptions. The fries and soda were found uneaten inside the room as well. The only thing missing was a pair of Teresa's sandals and the clothes she had been wearing. The front door to the family's residence was closed but unlocked.

Teresa had on several previous occasions left her home of her own accord, but she always maintained contact with her loved ones and has never been gone for more than a week. Authorities classified her case as that of an Endangered Runaway. She was junior at Sandia High School at the time of her disappearance; she was in special education classes due to her learning disabilities.

Teresa's mother received a phone call from an unidentified man in July 1999, one year after her daughter disappeared. The individual claimed to have information concerning Teresa' whereabouts, but demanded to be paid for his efforts. Teresa' mother's caller ID specified that the man was calling from the Econo Lodge motel on Central Avenue and San Pedro Drive Northeast in Albuquerque. She contacted authorities and a detective visited the business shortly afterwards. He found the caller, who told the officer that a young woman matching Teresa's description had been seen near the motel with a Cuban male known as "Oscar" who sold the caller some drugs. Oscar, the caller said, drove a white Maxima. Another woman, identified as Monica, had also been with him.

Authorities located Monica, a prostitute, who said that she had spoken to Teresa at a nearby laundromat and the girl gave her name as Terry and claimed she would return home when she was ready. Monica believed Terry may have been working the streets for Oscar. Neither of the sightings has been confirmed.

Teresa's mother contacted private investigators in May 2000, nearly two years after her daughter vanished. The detectives spoke with Teresa's cousin, Tyffani Sedillo, who spent the majority of July 1, 1998 with Teresa prior to her disappearance. Sedillo said that they visited friends near 4th Street and Griegos Avenue in Albuquerque during day. The girls were approached by five unidentified Hispanic men at the Phillips gas station at the intersection early in the evening. Sedillo said that the men invited them to a party which was being held later that night at Fourth Street and Montano Road Northwest in Albuquerque, behind a Phillips 66 gas station.

Her cousin was not interested, but Teresa took one of the men's phone numbers on a napkin and apparently wanted to attend the event. The men lived in one of the residences north of the gas station. They were described as being approximately 20 to 21 years old, all with shaved heads and wearing baggy pants. One was very thin, another was overweight, and the other two were average build. The men were driving an older-model cream-colored van that was in good condition and had no lettering or other markings on it. Sedillo drove Teresa home later in the evening and they did not talk about the men they had seen, but told investigators that she believed Teresa may have attempted to contact the men later that night. Sedillo left Teresa's house at 11:00 p.m., and half an hour later, Teresa bade her parents goodnight.

Sedillo also mentioned that Teresa may have placed the men's phone number inside of a plush toy in her bedroom. Teresa's mother checked and found the number tucked inside one of her daughter's stuffed animals. The number turned out to be from a disconnected cellular phone. Authorities do not know who the phone belonged to because a warrant is required to get that information and they do not have the evidence required for a warrant.

Teresa's mother has contacted several psychics for information they might have on her daughter's case. The psychics believe Teresa may have survived for a time after her disappearance but is now dead, and that possibly her disappearance and presumed death are drug-related. There is no evidence to support the psychics' assertions, however.

Teresa's family has since moved out of the apartment building where she lived, but they are still searching for her. Her family lives in Albuquerque and Las Cruces, New Mexico. Teresa's family has criticized the police investigating her disappearance. Her case remains unsolved. It was reclassifed from a runaway to an endangered missing person several years after her disappearance.