CNN  — 

A man and a woman were finishing dinner at a restaurant at the Downtown Aquarium in Houston, Texas, Thursday night when a man seated at the other end of the bar got up, approached the pair and opened fire, officials said.

When police arrived at the scene of the Downtown Aquarium, a 28-year-old man was dead and his 24-year-old wife was injured by gunfire. She was taken to a local hospital where she’s being treated and is in stable condition, according to police.

Police, via Twitter, called the shooting “a tragic, isolated incident” and said there was “no relationship” between the victims and the suspect.

The suspect was identified as Danny Garcia Cazares, 39, who police said had a previous criminal history and a history of mental illness.

The suspect “immediately started firing rounds” after approaching the pair shortly after 8 p.m., said Matt Slinkard, the Houston Police Executive Chief.

“The deceased male immediately went down, the female was injured, went down as well,” he said.

Then the male suspect killed himself, Slinkard said.

Homicide investigators are working to determine what led to a shooting, the chief said.