LA MESA (CNS) - La Mesa police Tuesday were investigating an armed robbery in which two employees at a frozen yogurt shop were tied up but not injured by a masked bandit.

The armed robbery at Golden Spoon Yogurt at 5640 Lake Murray Blvd. was reported about 9:45 p.m. Monday, according to La Mesa police.

The robber knocked on the front door to the business after closing time and wielded a silver handgun as he ordered an employee to unlock the door. Once inside, the suspect ordered that employee and another one into a back room, where one of the employees was restrained with zip ties, police said.

The unrestrained employee was then ordered to give the suspect money from the business' safe and cash register, according to police, who said once the money was given, the thief tied up the second employee.

He fled with an undisclosed amount of money. It was not immediately clear how the employees were freed.

Police described the suspect as black, in his 30s, around 5 feet 10 inches tall, with a medium build and possibly a deformity to one of his eyes.

He was last seen wearing a dark jacket, construction-type boots, white gloves and had a sheer scarf or type of mask over his face, police said.

Anyone with information about the crime was asked to call La Mesa police at (619) 667-1400. All tips can be made anonymously.