Bryan Kohberger's attorneys cited recent media coverage.
They say a Dateline NBC episode included leaked information that was not to be released to the public until trial.
The episode featured extensive records from Kohberger's phone, including internet and Amazon searches, Instagram photos and cell phone tower data.
Last week, a judge ordered prosecutors and defense attorneys to preserve those records.
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Kohberger's attorneys also cited a book on the case -- set to publish before the trial -- which also appears to contain leaked information.
They also said they need more time to process the discovery.
Kohberger's attorneys did not suggest a new trial date.
Jury selection is set to begin in late July, with the trial to start in August.
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If convicted, Kohberger could face the death penalty.