HOUSTON -

Four masked men walked into a northwest Houston Denny's and robbed the customers at gunpoint Sunday morning.

It happened at the restaurant on Farm to Market Road 1960 around 4:20.

According to reports, four men in a green Nissan Altima pulled up in front of the Denny's and went inside holding semi-automatic hand guns, police said.

They forced the employees and about a dozen customers to the ground and took their cell phones, wallets, and cash from the register, investigators said.

At one point, one of the suspects stepped on the back of a woman who was on the ground, police said, but no one was seriously hurt.

Police said the suspects got away with an unknown amount of items.

This is the third time this year the same Denny's has been robbed at gunpoint, police said.