HOUSTON -

Three teenagers are under arrest months after investigators say they held up employees and opened fire inside an adult novelty shop.

For four months, investigators have wondered who robbed a Katz's store in north Houston. They say they caught the three teens because one of them was bragging at school.

Surveillance video captured inside the Katz 24-hour adult novelty store on the North Freeway shows the three teens go inside and start firing shots. Investigators say they had no idea what they were doing as one suspect fired and scared his friend who fired too, hitting glass and a mannequin.

"They just start shooting the place up. Saw the video there, just randomly shooting at the business," said Jeff Brieden, with the Houston Police Department.

At the time, police described the trio as clumsy criminals. Houston police say the 16-year-old suspect looked up "clumsy robbers Houston, Texas" on a computer at his Aldine ISD school and bragged to his classmates. Someone told school police.

"The 16-year-old stated that he went into the robbery and had his finger on the trigger during the robbery never having handled a weapon like this before. Which made him all the more dangerous," Brieden said.

Police arrested the 16-year-old who they say carried an M-14 rifle in the robbery and shooting. Police also arrested two other 15-year-old suspects.  The three were arrested even though they tried to hide their identity during the robbery.

"Just because your face is concealed during a robbery doesn't mean you can't be charged," said Brieden.

Houston police say the three suspects now sit in the Harris County Juvenile Detention Center and face charges of aggravated robbery with a deadly weapon.

Police said it would be up to the district attorney as to whether the teens are tried as adults.