Four people were found shot to death after gunfire erupted at two homes in a neighborhood in Killeen, Texas, on Monday.

A 30-year-old man shot three people in one home before forcing his wife back to their neighboring house, where the two were later found with fatal gunshot wounds, Killeen police said in a statement. While four unidentified people died in what police are calling an apparent murder-suicide, one of the victims was hospitalized for suffering serious injuries.

On Sunday night, authorities were contacted over reports of domestic disturbance. After reaching the crime scene, they found three gunshot victims in the first house, CBS News reported.

Upon learning that the suspect and his 28-year-old wife had escaped back to their house on the same street, a standoff developed with the suspect holed up inside his home while SWAT team members surrounded it.

Soon after, gunshots were heard coming from inside the suspect's house, Killeen police spokeswoman Tina Amerson said. Two hours later, the suspect and his wife were pronounced dead by Justice of the Peace Garland Potvin, who ordered autopsies of the four victims at the Southwestern Institute of Forensic Sciences in Dallas.

A preliminary investigation showed that the gunman shot two women, ages 29 and 41, and a 40-year-old man at the first home, Reuters reported. However, the wounded 41-year-old woman was taken to a hospital and listed in serious condition.

Meanwhile, authorities did not release the victims' names pending notification of their relatives. The shootings remained under investigation, according to the Associated Press.

In another incident, a shooting killed three people, including the suspect who was a former police officer, and also left a county sheriff and a deputy wounded on Sunday in what authorities described as an ambush in northeastern Georgia.

The suspected gunman has been identified as 41-year-old Anthony Giaquinta, a former Gainesville, Ga., police officer. The Atlanta Journal-Constitution reported that Giaquinta had recently been fired.