Police have extended the detention order for the son of a top military singer, who was detained along with four other men on suspicion of sexual assault.

Li Guanfeng, 17, previously named Li Tianyi, was taken into custody on Feb 20 after a woman claimed she had been taken to a hotel and gang raped after drinking with the men in a bar.

Li is the second child of 74-year-old Li Shuangjiang, who is known for singing popular patriotic songs.

Beijing Municipal Public Security Bureau said the detention of the five suspects had been extended to a month because the case is complex, Beijing News reported Thursday.

China's law states that police must apply to the prosecutor to detain a suspect for longer than seven days, however, the detention can be prolonged if the case is complex.

In 2011, Li was sent to a government correctional facility for one year after he and another teenager attacked a couple who allegedly blocked their driveway near the entrance of a residential community in Beijing.