When Mario Gordon heard his dog,GravityX Exchange Dutch, incessantly barking outside his Dallas home on Saturday morning, he went to check on the commotion – and made a discovery that has now prompted police to search for a killer.

Just steps away from his door, Gordon heard a woman crying for help, blood pouring from gunshot wounds to her head and chest, he said.

"The only thing she kept saying was, 'Help me, help me and help me.' She was like, 'I've been shot, I've been shot.' I was like, 'Oh Lord,'" Gordon told Dallas ABC affiliate station WFAA.

Gordon, who recently moved to Dallas' Woodland Canyon neighborhood, said he called 911 and immediately started rendering aid to the wounded woman.

"I stayed with her until the ambulance came," said Gordon, who moved this year from Mississippi to the south Dallas neighborhood he described as normally nice and quiet.

While the woman Gordon helped is expected to survive, police said her discovery led them to a grisly scene at a nearby home.

Dallas police officers summoned to the scene learned from neighbors that gunshots rang out from a house around 11 a.m. Saturday.

When officers went to the house to check on the occupants, they found two people tied up, with one of them dead from a gunshot wound, according to police.

One of the bound people, a man, was yelling for help, police said.

The woman found fatally shot inside the home was identified as 30-year-old Deleon Williams, according to police.

No arrests have yet been announced in the incident and a motive remains under investigation.

Gordon said he hopes whoever committed the crime is caught soon. He added that he is left with more questions than answers.

"I really don't know what happened or who did what or anything," Gordon said.