HOUSTON -

Police are looking for a man they believe shot and killed his girlfriend after an argument in their southwest Houston apartment on Monday.

Houston police said she was shot inside a unit at the Victorian Apartments in the 9400 block of Coventry Square near Bissonnet shortly before 7 p.m.

Investigators believe the two got into some kind of argument before the shooting. The woman was shot once in the head.

Police said a man called his roommate and said he had shot a woman to death.

"The person of interest called his roommate and told him pretty much what happened, then he called the police," said Carlos Cardenas of the Houston Police Department. "Trying to see if we can find the possible suspect. We have someone in mind. Still trying to see if we can locate him."

The victim is in her 30s or 40s. Her name was not released.

Police said there is no sign of a struggle inside the apartment. Investigators have not yet released the name of the wanted man.