The Roman Catholic Church in Germany has terminated an independent inquiry it commissioned into sexual abuse by clergy, citing a breakdown in trust.
It said that bishops' trust in Prof Christian Pfeiffer, head of the Lower Saxony Criminological Research Institute, had been "destroyed".
Prof Pfeiffer accused the Church of obstructing his team's work by seeking to control the investigation.
The Church said a new inquiry would be commissioned with a different partner.
Bishops approached the institute in 2011 after a wave of revelations about sexual abuse broke and tens of thousands of Catholics deserted the Church.
Hundreds of people had come forward to say they were abused as minors between the 1950s and 1980s, amid suspicion the crimes were concealed.
Pope Benedict XVI, the German-born head of the Catholic Church, met victims when he visited Germany in 2011, and abuse survivors have been offered financial compensation.
Prof Pfeiffer went public about his concerns, telling German media that Church officials had hampered his team's research efforts by continually intervening.
Speaking to the German national broadcaster ZDF, he accused the Church of seeking to censor the research and trying to dictate the make-up of his team.
"We were meant to submit everything for approval," the professor said.
His team consisted of retired prosecutors and judges and was allowed access to personnel records on Church employees going back more than a decade, the German broadcaster Deutsche Welle reports.
The German Bishops' Conference announced that it had ended its co-operation with Prof Pfeiffer's institute.
"The relationship of mutual trust between the bishops and the head of the institute has been destroyed," the Bishop of Trier, Stephan Ackermann, said.
"Trust is vital for such an extensive project dealing with such a sensitive issue."
About 34% of Germans are officially Roman Catholic, according to recent figures.