According to the Harris County Sheriff's Office, deputies responded to the scene located at the Dunkin' Donuts in the 12600 block of State Highway 249.
When they arrived at the scene, deputies found the victim on the sidewalk with severe head injuries, officials said. The victim was treated by EMS and taken to a nearby hospital, authorities said.
According to investigators, employees of the Dunkin' Donuts gave deputies a description of the possible suspect, who was riding a bicycle. Officials said deputies found a man on a bike who fit the description and detained him.
While they were responding to the scene, deputies received a call about a second aggravated assault in the 13700 block of SH 249, within two miles of the first scene, with the victim reportedly having similar injuries.
Officials have not confirmed at this time that the two scenes are related.
HCSO said its detectives are investigating both scenes, as well as interviewing the detained man.