The Vatican is investigating seven priests from the Legion of Christ religious order for alleged sexual abuse of minors and another two for other alleged crimes.
In a statement, the Legion confirmed it had referred seven cases of alleged abuse to the Congregation for the Doctrine of the Faith.
All but one of the seven cases involves alleged abuse dating from decades ago; one case involves recent events, the Legion said.
A preliminary investigation cleared two other priests accused of abuse, the order said.
The investigations mark the first known Vatican action against Legion priests for alleged sexual assault following the scandal of the Legion's founder, who was long held up as a model by the Vatican despite credible accusations - later proven - that he raped and molested his seminarians.
The Legion has insisted that the crimes of its late founder, the Rev Marciel Maciel, were his alone.
But the Vatican investigation of other Legion priests indicates that the same culture of secrecy that Maciel created within the order to cover his crimes enabled other priests to abuse children.
Maciel died in 2008 and a year later the Legion admitted he had fathered three children with two different women and had abused his seminarians.
The Vatican took over the Legion in 2010 and is pushing through a process of reform.