SAN FRANCISCO, CA -- El Paso native Richard Ramirez who became infamous as the Night Stalker serial killer in Southern California is a suspect in another murder.

This one involves the murder of 9-year-old Mei Leung in San Francisco in 1984.

Ramirez is already on California's death row for 13 other murders.

San Francisco police said detectives this week served a search warrant on Ramirez to get his DNA.

"Ramirez complied with the search warrant. ... And at this time, we're not going to reveal any evidence that may have been obtained from that search warrant," said Chief David Shinn with the San Francisco Police Department.

Investigators said Ramirez lived in San Francisco at the time of Leung's murder.

She was sexually assaulted and killed in the basement of her home.