A Chinese national who allegedly fled to Hong Kong after killing his teenage nephews in the United States said he would surrender to US authorities, Hong Kong's Eastern Magistrates' Court heard on Monday.

Shi Deyun, sought by the United States for murder, was apprehended less than 24 hours following the discovery of the victims after disembarking a Los Angeles to Hong Kong Cathay Pacific flight, en route to Beijing on Saturday.

The nephews, 15 and 16 years old, sustained blunt force traumas with US investigators working on the premise that the killings were linked to a domestic dispute between Shi and his estranged wife who was seeking a divorce and restraining order in court on Thursday.

Shi allegedly went from the court to her Arcadia, California home and assaulted her. The two boys, sons of the wife's brother and sister-in-law, were left home alone as their parents accompanied Shi's wife to hospital.

Shi is understood to have broken into his nephews' home while the parents were away in the evening.

The boys' bodies were not discovered until the following morning after the parents went straight to bed after escorting Shi's wife to hospital.