A South Korean man stabbed his wife, son and sister-in-law before jumping to his death early Wednesday morning from the eighth floor of a Tokyo apartment building, police said.

Cho Yong Su, 46, got into a quarrel with his 41-year-old wife and stabbed her, their 14-year-old son and the woman's older sister at around 4:15 a.m. in their ninth-floor apartment in the building in Shinjuku Ward, police said.

The wife, Cho Myong Son, a South Korean permanent resident of Japan who also goes by the name of Akiko Miyake, is unconscious and in critical condition, police said. The two others suffered serious wounds.

Police said they plan to ask prosecutors to pursue a charge of attempted murder against Cho Yong Su on suspicion of attempted murder, even though he is dead.

According to police, Cho, a native of South Korea who entered Japan in April 2001 with the status of spouse of a permanent resident, got into an argument with his wife after they returned home early Wednesday.

He grabbed two knives from the kitchen and then stabbed the three victims, police said. The couple's 18-year-old daughter was in the apartment at the time but escaped unhurt, they said.

After the stabbings, Cho made his way to a balcony on the eighth floor and then jumped to his death soon after police arrived, a neighbor who witnessed the incident said. The knives where found near his body, police said.

A milk deliverer had called police after hearing a voice crying for help.

According to the couple's relatives and neighbors, the two often quarreled over talk about breaking up.