Houston, TX – A disturbing new development has emerged in the ongoing search for 24-year-old Sydney Marquez, a recent Texas A&M University graduate who vanished in southwest Houston on December 11, 2025. Recently, previously unseen CCTV footage capturing moments from her disappearance – including scenes near her abandoned vehicle left with the engine still running – has suddenly gone viral on social media platforms.

The video, which shows Sydney in the area around Bellaire Boulevard in Houston’s Asiatown district, has sparked intense online speculation. However, authorities are now urgently calling for the public to delete and stop sharing the clip, warning that its unauthorized spread could seriously complicate the active investigation.

Sydney, originally from El Paso, had traveled to Houston to visit friends. She was last confirmed seen around midnight on December 11, walking alone in the 9100 block of Bellaire Boulevard. Surveillance clips released earlier by family and search teams depicted her calmly walking northbound along Ranchester Drive, with no visible signs of distress. Her vehicle was later discovered abandoned nearby, engine idling, containing personal items like her phone and belongings – raising immediate concerns.

Family members have revealed that Sydney had been diagnosed with bipolar disorder and possible schizophrenia, and was not consistently taking her medication at the time. Her father, Raul Marquez, has been vocal in interviews, describing the ordeal as a “nightmare” and emphasizing that she appeared to be heading toward her hotel but never arrived.

The Houston Police Department, alongside volunteer organization Texas EquuSearch, has been leading extensive ground searches and following leads, including reviewing METRO bus footage after witnesses suggested she may have boarded one. Tips have been pursued in areas like Harwin Drive and Gessner Road, though many have not panned out.

The sudden leak of this additional CCTV material – reportedly showing critical scenes involving the running car and her final movements – has alarmed investigators. Spreading such evidence publicly risks contaminating witness accounts, encouraging false tips, or even alerting potential suspects if foul play is involved. While no evidence of abduction has surfaced and the case is treated as a missing person with mental health factors, police stress that uncontrolled dissemination could hinder progress and jeopardize Sydney’s safe return.

As of early January 2026, over three weeks since her disappearance, Sydney remains missing. She is described as 5’4″, 120 pounds, with short reddish-brown hair, brown eyes, glasses, and a distinctive four-leaf clover tattoo on her left wrist. She was last seen wearing gray pants, a gray hoodie, and tennis shoes.

The family continues to plead for information, urging anyone who spots Sydney to contact authorities immediately rather than approaching her, given her potential vulnerability. Houston PD can be reached at 832-394-1840, or Texas EquuSearch at 281-309-9500.

This case highlights the double-edged sword of social media in missing persons investigations: while it can amplify awareness, unchecked sharing of sensitive evidence may create unforeseen obstacles. Search efforts remain intensive, with hopes that responsible public cooperation will lead to answers soon.