"I had also seen him pin her daughter down on the sofa and slap the girl's bottom."
You mentioned sitting before three elders. The presence of three elders usually indicates the matter has advanced into an official judicial committee. Before that occurs, an accusation is typically first investigated by a pair of just two elders, who then report their findings to the entire body of elders to reach concensus whether an official judicial committee (of three or more) should be formed to judge the accused person.
Besides you, was the daughter or any other eyewitnesses willing to step forward with testimony to those elders. If so, by WT policy, that should have established real substance to the matter by means of their two or three "witness rule"
If you were the only person raising this accusation to those JW elders, that is like bleeding in shark infested water... JW elders and the accused person will attack as they did to you, usually threatening DF for lies/slander/apostasy/etc...
Major flaw there in "Jehovah's clean organisation"
Sometimes JWs will swing to the other extreme. There was a brother, average quiet single chap, that was accused of brushing up against a married sister's buttocks in a crowded area of the KH where many mingle after a meeting. He denied it. She brought in, as her eyewitness, the woman she had been talking with at the moment she felt contact on her butt. The "eyewitness" stated she did remember a sudden facial expression of alarm on the sister's face but did not notice the brother actually make contact while walking past behind the accuser. The accuser insisted it "felt like a quick grab" on her buttock.
Again, the brother acknowleged he had been mingling among the crowd but denied deliberately touching the sister.
The accuser and her "eyewitness" got emotional over the situation, and had managed to get the gossip about the matter spread into multiple congregations. The accuser's husband even asked everyone to drop the matter.
End result was the body of elders and circuit overseer decided the accusation had not been adequately established, (judicial committee was not deployed) however, notoriety of the fiasco had reached a level where the brother, though technically viewed as innocent, was nevertheless deleted (under his protest) from special privileges and asked to keep a low profile because many of the uninvolved sisters that heard about it reportedly "feel uncomfortable around him"...
This carried on for several years, and he eventually had to leave the area hoping to get a fresh start, but some among that body of elders ensured the mess was mentioned in the letter of introduction routinely sent to his new congregation (overseas) That new congregation responded by requesting clarification because the brother was showing fine fruits of mature spiritually in his new congregation. Branch offices got involved... the brother is still, years later, not permitted to have any special privileges of service in the congregation. All of this from what is considered an unsubstantiated accusation.
Surprisingly, the accused brother remains loyal to the borg.
It is upsetting to see how feckless WT can be when "handling" accusations, particularly accusations of the sexual sort.