Summers, 32 -- sought for the alleged kidnapping and sexual assault of a 10-year-old Los Angeles girl -- was spotted on video footage crossing the border into Mexico this week.
LAPD Chief Charlie Beck told reporters Friday it was not known where Summers went after he entered Mexico at the Tecate crossing.
The head of the state police in Baja California told the Los Angeles Times officers were on the lookout for Summers in the coastal cities of Tijuana, Ensenada and Rosarito Beach, as well as Tecate.
"We want to find the guy before he rapes a Mexican kid," said Alfredo Arenas, who heads the state police fugitive squad. "We're thinking that he did cross the border and he is on our side of the fence, but we don't know exactly where."