LEAD: 20 at Sendai clinic suffered after treatment by suspect.
(EDS: UPDATING WITH POLICE FINDING OF RELAXANT IN OTHER VICTIMS)
As many as 20 patients at a hospital in Sendai, northeastern Japan, died or fell into a critical condition apparently at the hands of a 29-year-old male nurse arrested on suspicion of attempting to kill an 11-year-old girl, police sources said Wednesday.
Of the 20 patients, about 10 died, seven or eight are still in a serious condition and the remainder have recovered after allegedly being administered muscle relaxant and possibly other drugs intravenously by the nurse, Daisuke Mori, the sources said.
Mori was arrested Saturday on suspicion of attempting to kill the girl by intravenously administering her with dangerous levels of muscle relaxant at Hokuryo Clinic.
After the 11-year-old girl became critical on Oct. 31, the clinic restricted staff access to muscle relaxant drugs and took blood samples from three patients whose conditions had deteriorated suddenly after intravenous treatment by Mori during the following month.
Police said they detected muscle relaxant in two of the three samples -- one of a 90-year-old woman who has since died and another from a four or five-year-old boy who suffered a sudden worsening of his condition.
The woman was admitted to the clinic from a nearby nursing home with a fever on Nov. 15 and died Nov. 24. The clinic then determined the cause of death as cardiac infarction.
Police said they found in the third blood sample -- taken from a five-year-old boy who was not seriously ill -- another drug which they suspect was also administered by the nurse.
Mori worked as a licensed practical nurse at the clinic for 22 months until he quit Dec. 4.
The girl, who remains unconscious, had traces of a muscle relaxant comprising vecuronium bromide in her blood.
The suspect admitted to attempting to kill her and also confessed to administering relaxant to other patients, according to police.
Four elderly patients from the same local nursing home have died at the clinic since July 1999, and investigators suspect Mori's involvement in their deaths, police said.
An 85-year-old woman who was admitted July 15, 1999 for dropsy and a lack of appetite died the following day from heart failure, and an 88-year-old woman who entered the clinic on Nov. 16, 1999 died two weeks later, according to sources at the nursing home.
Two women, age 89 and 94, were admitted Feb. 16, 2000. One died the same day and the other three days later, they said.
Investigators say they are gathering evidence with the aim of charging Mori for murders, attempted murders or otherwise.