TORONTO -- An intensive, three-month homicide probe at one of North America's most renowned children's hospitals has plunged deep into uncharted medical territory that has yielded few clues to the deaths of 43 infants.
At least four of the deaths were confirmed as murder cases and a fifth was added by a judge who absolved the only suspect to date, a young nurse at Toronto's Hospital for Sick Children.
The clearance of pediatric nurse Susan Nelles prompted the Ontario government to order police to reopen their investigation and expand it to include all 43 infants who died in the hospital's cardiac care unit between July 1980 and March 1981.
Close-mouthed investigators have confirmed only the exhumation of five more infants, none publicly identified. Even families, some in agony more than a year over why their babies died, received little more information.
'It's horrible,' said Adrian Hines, father of one of the possible victims. 'My wife and I have often said things will be better when they get back to normal. But it's hard to remember what 'normal' is like. We have to wonder now if there ever will be a 'normal.''
More than 25,000 patients annually undergo care from the 3,200-member staff of the 700-bed 'Sick Kids,' largest children's hospital on the continent and known for pioneering procedures in treating children's ailments.
But 16 months ago, attention focused on patients who had died instead of those who had been saved. Police arrested Miss Nelles, 25, daughter and sister of doctors, and charged her with the murder of four babies who had died of massive overdoses of digoxin, a powerful form of digitalis widely used to regulate heart rate.
In May, Judge David Vanek ended a 44-day preliminary hearing by declaring murder had been committed, but not by Miss Nelles.
'I am satisfied that there is sufficient evidence to go to a jury with respect to the four infants in question,' Vanek ruled. 'The only remaining question ... is -- who did it? There is evidence that points in a different direction (from Miss Nelles).'
Almost anyone familiar with medical procedures could have done it.
'You don't have to be very intelligent to use digoxin as a murder weapon. All you need is access,' said Dr. Alois Hastreiter, of Chicago, one of the world's few experts on digoxin who has been aiding Toronto police.
'But ... the fact that someone has yet to be caught indicates some degree of intelligence.'
The hearing for Miss Nelles was closed, as permitted under Canadian law. But after her discharge, its proceedings were open to publication.
It emerged that the defense had brought forth evidence on 17 deaths involving digoxin and following the pattern of the four deaths in which the nurse had been accused.
Along with the expanded police inquiry into all the deaths that had occurred in the cardiac unit during the eight-month period, the government also appointed an inquiry into all procedures in effect at the Sick Kids hospital.
The hospital also faces three legal writs charging negligence.
Miss Nelles has taken a long vacation, unsure if her future includes a nursing career.
And police, still smarting at criticism they moved too hastily on slim evidence against Miss Nelles, give little indication they have any answers to the chilling questions about a killer still on the loose.
'Digoxin is a very toxic drug and would be a very good one to use as a murder weapon,' Hastreiter said. 'But ... no one has ever used it before.'
Since there was no prior record of murder by digoxin, no laboratory procedure existed for post-mortem detection or reaction of the drug in human tissue. But a team of forensic scientists forced to innovate testing methods found high levels of digoxin -- as much as 100 times the normal dosage -- in the tissues of at least five of the bodies.
But because of the uniqueness of the inquiry, experts are uncertain about the precision of their tests. Little is known about the effects decomposition has on the levels of the drug -- especially in bodies that have been buried as long as two years.
'The tissues are not as they were before death,' Hastreiter said from his University of Illinois office. 'There are many changes that can occur. In some cases the concentration will increase artificially. In other instances it could be just the opposite.'
The experts also found digoxin diffused throughout the body during decomposition, making it difficult to determine how or in what form the fatal dose was given.
'There is no one specific test that will tell us how the drug was administered,' Hastreiter said. 'But if you have enough information (from the field investigation), and you are able to put everything together, sometimes you can tell.'
Police, who said they are likely to exhume more bodies, have withheld any autopsy results to date.
'They don't even know whether the tests have worked,' said Supt. Frank Barbetta, one of only two police officers allowed to talk about the homicide investigation to reporters.
Supt. Robert Bamlett, head of the probe operating out of offices at the hospital, admitted police were 'far from the end of the investigation.' He added he 'hoped to see some light at the end of the tunnel' by mid-September.
Asked how many of the 43 deaths police now believe involved foul play, Bamlett said abruptly, 'I cannot answer that because it may prejudice the investigation.'
As the probe drags on, parents of the 43 babies grow more anxious.
'We've written to the hospital a number of times trying to get an explanation as to what happened, trying to find out how our son died,'
The hospital told Hines immediately after the baby's death that the cause was sudden infant death syndrome. A coroner advised the family last December the child had died of digoxin overdose. Jordan had not been prescribed the drug.
'He entered the hospital a healthy baby with a touch of pneumonia. He didn't even have a heart condition,' said Hines, a car dealer.
But, even after the coroner's diagnosis, the hospital reaffirmed its initial finding.
'How can they be content to say that now after all that has happened?' Hines said. 'I can understand how they might want to tell us it's still under investigation and they can't answer our questions, but to tell us crib death ...'
Hines said he also appealed to police and was told only 'they hope to have some answers in the fall.'
Hines follows the investigation avidly -- collecting clippings, spending long hours on the phone with police, doctors, coroners and reporters -- amid growing desperation and bitterness.
'They (the hospital) allowed this to go on, hoping it would go away, believing it was a medical problem. Now they know something is very wrong. I believe they are just following their legal advisers.'
Hines was referring to the hospital's failure to call police between July 1980 and March 1981, when the death rate on the cardiac ward climbed from a normal 1- per month to a startling five per month.
A second investigation under Ontario Supreme Court Justice Charles Dubin into medical procedures at the hospital also has yielded no public results.
Dubin's team includes acknowledged experts in their fields -- Dr. Henry Nadler, Dean of Pediatrics at Wayne State Medical School in Michigan; Dr. Hugh McDonald, president of St. Paul's Hospital in Vancouver; and Joan Gilchrist, director of McGill University's school of nursing in Montreal.
The hospital drew criticism for alleged slack procedures, especially in administration and security of drugs. Before the mysterious deaths of the babies, digoxin itself had not been listed as a dangerous, controlled drug.
The outcry intensified this spring when one baby died and 14 others fell ill on the neo-natal ward after receiving doses of adrenalin instead of vitamin E. A coroner's inquiry ruled the adrenalin death accidental due to poor labeling of the drugs.
Hospital administrator Kenneth Rowe said security has since been tightened. He also admitted the investigation has taken its toll on staff morale.
'Everyone is unhappy that the hospital is being blamed. A hospital has to be based on trust. We don't set up our practices to defend against homicide. They are all dedicated and it would be ludicrous for our staff to automatically think of foul play.'
Of the three legal writs against the hospital, two -- filed before the preliminary hearing discharge -- also named Miss Nelles.
Lawyers for the three plaintiffs said they would await the Dubin inquiry report before deciding on further legal steps, including the issue of damages.
Miss Nelles, on paid leave of absence from the hospital since her March 1981 arrest, has spent most of her time with her parents in Belleville, Ont., about 200 kilometers east of Toronto. She was judged in good standing by the nursing order following her discharge.
'She just wants to try and forget about everything. I can't tell you anything about her future plans,' her lawyer Austin Cooper said.
While the Nelles family is bent on retrieving a semblance of normalcy, the families of the victims agonize over their children's deaths. And somewhere a killer of babies eludes police and walks free.