Mystery of Chinese-American family shot to death in Houston home
Authorities have not yet determined a motive for the killings nor identified any suspects, Harris County Sheriff Adrian Garcia said on Tuesday. All four victims, including the boys aged 7 and 9, were shot in the head.

Investigators are baffled by the fatal shootings last week of a Chinese-American family of four, including two young boys, at their suburban Houston home.
Authorities have not yet determined a motive for the killings nor identified any suspects, Harris County Sheriff Adrian Garcia said on Tuesday. All four victims, including the boys aged 7 and 9, were shot in the head.
The names of the victims have not been released but local media identified the children as Timothy Xie Sun and his younger brother Titus Xiao Sun, both pupils at Sampson Elementary School. The two boys were last seen at school on January 23, although bad weather closed schools in the district on January 24 and 28.
Public records show the home at 14015 Fosters Creek belonged to 49-year-old Mei Xie and her husband Maoye Sun, 50. The couple were married in Harris County in November 2000.
Garcia said his office was working with the Chinese consulate to locate relatives. Authorities said the husband and wife were naturalised US citizens who had emigrated from China. They did not say when the family arrived in the United States.
Garcia said deputies went to the family's Cypress home last Thursday after the husband's colleagues became concerned when he had not shown up for work for several days. Deputies found the back door open and inside discovered a "horrific crime scene", Garcia said.