HOUSTON -- A man and woman were killed in what appeared to be a murder-suicide early Friday, officials told KPRC Local 2.

Houston police said a person reported that a woman may have been in trouble inside a home on Chew Street near Hershe Street at about 12:30 a.m.

Investigators said the woman, a private security guard, did not show up for work on Thursday. A co-worker called to check on her and got the impression that she was in danger.

"The caller stated that she was speaking in a code, trying to allow him to know something was going on," officer Brian Evans said. "He got the feeling that she was trying to do so without alerting the male occupant of the home."

Officers heard the woman screaming inside the house, but burglar bars prevented them from getting to her.

A tow truck was called in to pull the bars off the door, but it was too late.

"The burglar bars were forcibly removed and upon doing so the male and female were located inside the house, both deceased," Evans said.

Detectives said the couple had been dating about 6 months. The woman had told co-workers that she was having trouble in her relationship, police said.

The identities of the man and woman were not released.