According to AP, citing a spokesperson for the FBI, one residence is the home of his grandparents in Allen, Texas, where local authorities shut down streets following the gun massacre on Saturday.
Allen, located 20 miles (32 kilometers) north of Dallas, is an affluent community of about 100,000.
The United States was shaken on Saturday by two separate fatal shootings that are being described as acts of domestic terrorism by law enforcement agencies. At least 20 people were killed and 26 more injured after a gunman opened fire in a Walmart in the Cielo Vista Mall in El Paso, Texas, in the city of El Paso, Texas, on Saturday evening.
Hours later, another gunman attacked people in the city of Dayton, Ohio, killing nine and injuring at least 26.
US President Donald Trump ordered flags to be lowered to half-staff to to acknowledge the deaths, adding that he would make a statement on Monday about the shooting massacres.
The massacres, now being considered acts of domestic terrorism by law enforcement agencies, occurred just six days after at least 15 people were injured and four people were killed - including two children - during another mass shooting at an annual family festival in the California town of Gilroy.
