FBI agents joined the search Friday for a high school student from Pacoima who vanished a week ago during heavy rains.
Elias Rodriguez, 14, was last seen walking home from Cesar Chavez High School on the afternoon of February 17.
Agents joined LAPD and L.A. School Police officers in canvassing area businesses and homes for clues.
"We believe this case is unusual because Elias is not known to run away, have any problems, have any reason to be away from home," said LAPD Lt. Katie Burns.
Rodriguez left a voicemail message for his mother before he began to walk his usual route to his grandparents' home.
The path took him along busy Glenoaks Blvd., where investigators said they believe an image of Rodriguez was captured by a business's security video system.
The route would take Rodriguez across the Pacoima wash, which was flooded with rushing water around the time he walked home.
Police searched the wash but found no evidence Rodriguez had been washed away.
"They need to be more vigilant and not treat a missing report case just like a runway," said Rodriguez's aunt, Jessenia Vega.
She said she was worried police lost valuable time by not searching more aggressively when Rodriguez was first reported missing.
Dozens of officers and agents were involved in the expanded search Friday.
Investigators said they planned to visit every home and business, and interview every person, who lives or works along the route Rodriguez typically traveled.
-- Eric Leonard (@LeonardFiles) in Pacoima