The FBI is helping Oakland, Calif., police search for a 13-year-old girl and an elderly man who they believe were carjacked at knifepoint, authorities said today. Police have issued an Amber Alert, and are trying to track down the red sedan they believe the two are in.

"We are looking for and would like to locate person of interest. His name is Roy McCamey," Johnna Watson of the Oakland Police Department told reporters at a news conference.

A screen grab from a surveillance video shows the suspect of a carjacking and kidnapping in Oakland, Calif. (ABC News)

McCamey is only a person of interest, Watson said, but investigators would like to talk to him.

The incident happened Tuesday afternoon at a Safeway in Oakland, on Redwood Road. At about 12:50 p.m., store employees say the suspect, a 35-year-old black male, was caught stuffing lobster tails and rib eye steaks under his jacket. Surveillance video shows the man wearing a hat, silver headphones, a dark jacket and dark pants. The suspect left the store, knife in hand, according to local media reports.

That's when he got into the red Infiniti sedan with two people inside, police said. The suspect forced the man to drive away, witnesses told police, with the teenage girl in the back seat.

Police initially reported that the suspect jumped into an SUV, but after tracking the SUV to the East Coast, police believe the license plate may have been switched.

The sedan that police believe the suspect drove away in has four doors and a 2001 California license plate, 6JFM648.

Police said they don't know the identities of the older man or teenage girl. No one has reported anyone as missing as of this afternoon that matches the description of either victim, police said.

There is a $10,000 reward for anyone who can provide information leading to an arrest.