Daniel Cooke, 26, was arrested on Tuesday at his home on Michelangelo Court in Hockessin.
Cooke was arrested following an undercover online investigation conducted by the Delaware Child Predator Task Force, Attorney General Beau Biden announced.
Investigators say a search of Cooke's home revealed multiple files of child pornography, Biden's office said, "including a video of an elementary school-age female child engaged in sex acts with an adult male."
Cooke was arrested and charged with 25 counts of dealing in child pornography.
He is being held on $1.5 million bail.
Cooke allegedly told investigators that, at the time of his arrest, he had been employed as an assistant junior varsity soccer coach at the Tatnall School during the 2012-2013 school year.
Officials told Action News that a background check on him came back clean, and that there were no reported problems during his time at the school.A school spokesman also said Cooke was told the job would be for one year with no guarantee of further employment, adding they have not had contact with him since the season ended in November.
No one answered the door at his home.
Neighbors say Cooke lived there with his mother and brother, but they largely kept to themselves.