A 37-year-old Kauai man is facing a federal prison term of between 15 and 30 years for video recording himself sexually assaulting children in his Lihue home when the children were between 7 and 13 years old.

Michael Terui pleaded guilty in U.S. District Court on Tuesday to four counts of sexually exploiting children. Each charge involved a different boy and carries a mandatory minimum penalty of 15 years in prison and a maximum of 30 years. Terui is also facing up to a lifetime of court supervision and registering as a convicted sex offender after he completes his prison term.

U.S. District Chief Judge J. Michael Seabright scheduled sentencing for June.

Terui’s lawyer William Harrison told Seabright he may ask for a later sentencing date as he tries to resolve related state sexual assault charges against Terui and anticipated civil lawsuits from the children’s families. He said he also intends to have Terui undergo psychosexual evaluation.

Assistant U.S. Attorney Marc Wallenstein told Seabright that Terui recorded himself sexually assaulting eight children in his custody between 2008 and 2016, while most of them were sleeping. He said Terui also had hidden cameras to record the children in the bathroom and shower.

As part of his plea agreement, Terui will be allowed to withdraw his guilty pleas if an appeals court rules to throw out his statements made to Kauai police and all evidence law enforcement recovered based on those statements.

Seabright ruled in September that the government can use the evidence and statements to prosecute Terui. The evidence includes digital images the FBI recovered from electronic devices from Terui’s Kaneka Street home.

Kauai police seized the devices in February after Terui told them he had sexually assaulted a number of boys and girls over a span of eight or nine years. Terui made the admission after he agreed to and completed a polygraph examination. He claims police did not warn him that his post-polygraph examination statements can be used against him.

Police questioned Terui as they were investigating a sexual assault complaint involving one of the eight children in the videos. A state grand jury indicted Terui in February on two counts of sexually assaulting a minor. The grand jury indicted Terui in August on five more counts involving two other boys in the videos.

One of the state cases is scheduled to go to trial in January. The other is scheduled for April.