A man cleared by a jury of killing his 20-month-old stepdaughter in a "shaken baby syndrome" case probably did cause her death, a family judge ruled yesterday.

Mr Justice Hedley said: "The man at the centre of this has already been tried for and acquitted of both murder and manslaughter yet the family court is apparently retrying the same issue with the inevitable possibility of arriving at a different view."

The man, identified as W, was accused of pushing the child away so forcefully that she fell from his bed and hit her head. He now has to wait for a further hearing to decide whether his own 15-month-old child is at risk and should stay in care.

Mr Justice Hedley gave his ruling in open court because, he said, there were issues involved which needed to be in the public domain.

The case involved the death of a child said to have been caused by shaken baby syndrome where there had been disagreement between medical experts.

W was not the father of the victim, X, but lived with the mother, S, and acted as the child's father. The care proceedings involved the daughter of W and S, whom the judge called T.

Mr Justice Hedley said no one would ever know for sure what happened to X immediately before she suffered fatal brain injuries on the morning of October 20 2002.

He was convinced that W had no malevolent intent towards the girl and agreed with the jury that he had not been guilty of murder. But it was probable that the girl was sick or about to be sick and he had pushed her away with such force that she rose above the height of the bed and fell.

"I am quite satisfied that his action was culpable," he said, "in that it was an action performed by him that he should have realised was potentially dangerous."

This was "technically inconsistent" with the jury's manslaughter findings, but he understood the "reluctance to expose him to criminal punishment in the circumstances".

The man genuinely loved and cared for his stepdaughter and as a general rule was gentle and competent. "This was an uncharacteristic reaction to a situation."

There will be a further hearing to decide whether T should remain in care and the amount of contact she will have with her father.

The judge said that in the criminal proceedings the jury had decided that they were not sure whether W had used criminal violence which had caused the child's death.

But it was not known whether they had found him innocent, or probably guilty but they could not be certain.

"In family proceedings, however, the judge's task is quite different. In the end, I will have to decide whether the surviving child T can be safely returned to one or both of her parents.

"[The jury] were primarily concerned with W as the defendant whilst I am primarily concerned with the child."

The standard of proof required in the family court was lower, he added.