Harris County Sheriff Adrian Garcia said investigators are waiting for an opportunity to interview the two survivors. Both are in critical condition at Memorial Hermann-Texas Trauma Institute in Houston.
The shooting happened late Wednesday afternoon at an apartment complex in an unincorporated area 25 miles northwest of downtown Houston.
Garcia says a young man and two young women died after each was shot multiple times, including in the head. The surviving man and woman had similar gunshot wounds.
Deputies have no description of the gunman. Garcia says witnesses reported a man shot the victims inside the one-bedroom downstairs apartment, closed the apartment door and fled.