EL PASO, Texas (AP) _ A 5-year-old girl, missing for a year and a half, was in the care of Mexican child welfare officials while a search for her was conducted across the United States.

The girl, Angelica Marinquez, and her mother were reunited this week, the El Paso Herald-Post reported.

The media in El Paso, and just across the border in Ciudad Juarez, Mexico, had given her case extensive publicity, and it also was discussed in March on the national television program ''America's Most Wanted.''

Angelica disappeared from a downtown El Paso Greyhound station Feb. 17, 1990. She and her two brothers were left in the care of their uncle, who is mentally retarded. When their mother returned, the girl was gone.

Police first believed the toddler had wandered away. They later feared she had been kidnapped or sold.

Police now say the girl somehow got from the El Paso bus station to the Juarez bus station. There a woman, who has not been identified, asked another woman to take the girl because she could support her, police Detective Jesus Terrones said.

The second woman took the child and reported the incident to security guards, who told her they couldn't do anything, Terrones said. The woman then took Angelica with her to the city of Chihuahua, Mexico, about 200 miles south, and handed her over to the Department for Family Development the next day.

The girl remained at a child welfare center in Chihuahua, where officials also released her picture to the media. A tip from a woman involved in another missing-child case led U.S. detectives to find her.

''The important thing is that she was found alive,'' said Detective Joe Molinar.