LA MESA, Calif. – A search for a masked man who attempted to rob a person at gunpoint in La Mesa Friday prompted a 30-minute lockdown of a nearby elementary school, police said.

The would-be robber’s intended victim had parked in the 5300 block of Maryland Avenue near Guessman Avenue shortly after 3 p.m., police said.

A man wearing a hard plastic mask and brandishing a large-caliber semi-automatic pistol approached and demanded the person’s wallet, according to a police statement.

After determining the victim was not carrying a wallet, the suspect ran east on Maryland Avenue empty-handed, police said.

No injuries were reported.

Officers and a helicopter crew searched the area, but did not locate the suspect.

Maryland Avenue Elementary School — classes had ended but after-school activities were taking place — was placed on lock-down for about 30 minutes, police said.

The suspect was about 6 feet tall and thin, was wearing a light gray hooded sweatshirt with the hood pulled over his hair, gloves and the hard plastic mask.

Police asked anyone with information to call them at (619) 667-1400 or contact Crime Stoppers at (888) 580-8477.