A man and woman were shot in the head at a home in northwest Houston early Saturday morning, authorities said.

According to the Harris County Sheriff's Office, they responded to a shooting call around 2:10 a.m. in the 10000 block of Rio Grande Street.

Upon arrival, they said they found a 30-year-old man and 35-year-old woman shot in the head. They were transported by Memorial Hermann Life Flight.

The man is in critical condition, and the woman is in serious condition.

Detectives said the weapon was at the scene of the crime; there was no sign of forced entry.

The investigation is ongoing.