A former Brooklyn Center student has told school officials that he had sex with a female teacher "over a lengthy period of time" in 2015-16 when he was in seventh grade, according to court records.

The teacher, now 38 years old, has been put on administrative leave as the police investigation continues, school district spokeswoman Olivia Doeden said Thursday.

The former student, now 21 years old, went to the school on April 6 with his allegations, according to a search warrant affidavit filed with the court that seeks permission to see all school records for the teacher and the former student, and any high school surveillance images "that may have been retained from the time around the reported sexual assaults."

A school official then relayed the accusations to police that same day.

Doeden said the teacher has been with the district since August 2013. The teacher graduated from the University of St. Thomas earlier that year. State records show her teaching license remains active.

Police Cmdr. Garett Flesland acknowledged that his department is investigating the report and has yet to forward a case to the Hennepin County Attorney's Office for consideration of charges. The Star Tribune generally does not identify suspects before they are charged.

According to the affidavit:

The former student said that the teacher performed oral sex on him and "engaged in ongoing ... intercourse with him over a lengthy period of time."

He said she was his English as a Second Language teacher, and they would have additional class periods during and after regular school hours.

The two "continued to have communication" after he left the school, which included exchanging pornographic emails and engaging in phone sex, the former student said.