If proved true, it should be a slam dunk.
Well, already the OP article states that "Terry ultimately plead guilty to indecent assault and corruption of a minor and was sentenced to prison and probation"
But, what about the Mandatory Reporting issue? Well, the elephant-in-the-room is:
Why on earth isn't Pennsylvania State themselves prosecuting for failing to mandatory report?? It's their law, it's there.... RESPONSIBILITY to uphold that law - so why evidently aren't they?!?
Who are 'Mandated Reporters'? Although the OP is a relatively recent case - the current law includes:
An adult family member who is a person responsible for the child's welfare and provides services to a child in a family living home
http://www.pa-fsa.org/Mandated-Reporters/Understanding-Mandated-Reporting/Who-are-Mandated-Reporters
The perpetrator's daughter - who apparently was the first to raise her suspicions with the victim's mother - does not seem to be a 'mandatory reporter'? (and evidently, neither is the perpetrator's adult husband?) , but the victim's parents would appear to be 'mandated reporters' - and they would also seem to have been the first 'mandated reporters' to become aware of the (OP) "intimate nature of the relationship".
Although there was a court case only a couple of years ago, and the perpetrator pleaded guilty - there appears to be scant information regarding the case online - fyi there is the following, though I can't vouch for the reliability of the website:
PENNSYLVANIA v. TERRY JEANNE MONHEIM was
a 2012-13 Pennsylvania criminal court case in which a Female Jehovah's
Witness named Terry Monheim, aka Terry Jeanne Seipp, then age 58, then
of Vandergrift, Pennsylvania, was arrested and charged with statutory
sexual assault, indecent assault on a person younger than 16 years old,
and corruption of a minor. Outcome unknown.
In
2011, the alleged Female victim, by then age 22, whom had been reared as
a third-generation Jehovah's Witness, reported to law enforcement that
she had been repeatedly sexually assaulted by Terry Monheim between 2003
and 2005, when the alleged victim was 14 to 16 years-old, and while the
alleged victim and Monheim had been fellow members of the Spring Grove
Congregation of Jehovah's Witnesses, in York County, PA. The alleged
victim further alleged that both she and Terry Monheim had been "publicly reproved" by
the Congregation -- for what the Elders at the Spring Grove
Congregation of Jehovah's Witnesses apparently had considered to have
been a consensual homosexual relationship. The alleged victim thereafter
publicly alleged that she also had been sexually assaulted by an
unidentified Male Jehovah's Witness when she was only 4 years-old.
Outcome unknown.
http://jwdivorces.bravehost.com/molestation4.html