ANN ARBOR, Mich. -- An Ann Arbor school bus driver was arraigned Saturday on three counts of second-degree criminal sexual conduct and one count of enticing a minor.

The 40-year-old male driver is under investigation for allegations of criminal sexual misconduct after a female student went to police, the district’s superintendent said.

Olu Osuntuyi turned himself in on Friday, the Ann Arbor News reported.

In a letter sent to parents Oct. 3, superintendent Todd Roberts said the district was informed about the allegations the previous day by the Ann Arbor Police.

“This driver has been suspended pending district and police investigations,” Roberts said in the letter. "The investigations are in the early stages. The district will continue to be in contact with the police during the investigations and will take appropriate action based on the outcome of the investigations."

"A student of ours had gone to the police department and reported some allegations regarding some type of sexual relationship with one of the bus drivers," said district spokeswoman Liz Margolis.

Ann Arbor Police Detective Sergeant Jeff Connelly said it appears Osuntuyi had a relationship with a 14-year-old girl, and that he used his position on the bus to manipulate the girl.

Connelly said the investigation is focused on the suspicion of inappropriate contact and time spent between the two.

Osuntuyi is from Ypsilanti Township and operated route 30, which serves Huron High School, Clague Middle School and Northside Elementary School.

"Every single employee goes through a complete criminal background check, including a fingerprint check, before they are employed," said Margolis.

Margolis said Osuntuyi had been employed by the district since 2002. He received a another check in 2007. "The police also said all of their checks totally came up totally clean,” Margolis said.

Another spokesperson for the district said none of the alleged incidents occurred on a school bus or school grounds.

"We are very disturbed by this," said Margolis. "This is an employee who has been with us and who has done a very good job."