BOSTON — A series of events in the months leading up to the criminal trial against former priest Paul R. Shanley have caused the case against one of the figures at the center of Boston’s clergy abuse scandal to be severely weakened.

Originally, prosecutors were thought to have an advantage in the case, which is expected to go to trial Jan. 18. Four alleged victims were prepared to testify that Shanley had molested them between 1979 and 1989 when they were altar boys at St. Jean the Evangelist Parish in Newton. However, over the past year, prosecutors were forced to drop charges related to two of the alleged victims and recently planned to drop charges related to a third.

The four alleged victims, all of whom settled civil lawsuits against the archdiocese, said their suppressed memories of abuse by Shanley were triggered after seeing news reports about the clergy sexual abuse scandal, which came to light in 2002.

Last July, prosecutors dismissed charges against Shanley in two of the cases, including charges brought by Greg Ford, the most public and outspoken of Shanley’s alleged victims. Prosecutors said they dismissed those charges in an attempt to strengthen their case. Ford, who has been admitted to psychiatric hospitals several times and made multiple suicide attempts, had given conflicting statements about when he recovered memories of the alleged abuse.

During a pretrial hearing in October 2004, the third alleged victim, now 35, was aggressively questioned by Shanley’s lawyer Frank Mondano about his admitted history of drug and alcohol abuse, how he came to recall the alleged sexual abuse and his claims that he was also sexually abused by a babysitter.

Middlesex County prosecutor Lynn Rooney said at the time that the man, who is homeless, became ill and vomited after Mondano’s cross-examination. She said prosecutors were unable to locate him after that hearing.

Earlier this month, a source familiar with the case told the Associated Press that prosecutors were set to drop the charges related to this third victim some time before the trial’s start date.

The remaining accuser left in the criminal case claimed that Shanley repeatedly molested him, from 1983 to 1989, beginning when he was 6. He began to remember the abuse in February 2002, after reading a newspaper story about Shanley.

In an attempt to shore-up what remained of their case against Shanley, prosecutors asked the court to bar the news media from naming the alleged victims. Prosecutors said they feared the lone remaining accuser would refuse to testify if media outlets continued to identify him by name.

On Jan. 4, Superior Court Judge Charles Spurlock issued an order barring the publication of the alleged victims’ names even though Shanley’s remaining accuser had been identified in media reports since 2002 and spoken publicly about his allegations in the past.

Spurlock cited a state law dating back to the 1980s that says that court or police records containing the name of victims in criminal cases involving rape or assault with intent to rape “shall be withheld from public inspection, except with the consent of a justice” of the court where the case is being prosecuted.

On Jan. 7, Middlesex Superior Court Judge Stephen Neel overturned Spurlock’s previous ruling that barred the media from identifying the alleged victims. The AP, the Boston Herald and The Boston Globe had challenged the order saying it was unconstitutional “prior restraint.” Neel agreed, but gave the prosecution time to appeal before allowing the media to identify the men.

Middlesex District Attorney Martha Coakley issued a statement Jan. 10 stating that the prosecution would not appeal Neel’s decision and would focus on preparing for the coming trial.

Shanley, who is free on $300,000 bail while he awaits trial, was initially charged with 10 counts of child rape and six counts of indecent assault and battery. He resigned from the Archdiocese of Boston in 1989 and moved to San Diego, where he was arrested in 2002. He was defrocked in 2004. Because Shanley lived outside of Massachusetts for a time, the statue of limitations, which has prevented criminal charges from being brought in many clergy abuse cases, was suspended.