Staff at a Cottage Grove high school seized the keys from a school bus driver as students were boarding; he was then arrested on suspicion of being under the influence of drugs or alcohol.

Officers were called to Park High School at 8040 80th Street about 3:10 p.m. Wednesday, a statement from police read, where school staff had already taken the keys from the bus.

"Additional officers arrived and found probable cause to arrest the 36-year-old man for DUI," the statement continued.

The man was released from jail Friday "pending the blood test results from the MN BCA [Bureau of Criminal Apprehension]," Police Capt. Greg Rinzel said in an email.

An officer at the scene said in a search warrant affidavit that cleared the way for collection of the driver's blood for testing degree of impairment that "I observed slurred speech, unsteady gait, red watery eyes and [constricted] pupils."

The man, who is from Hastings, is being held in the Washington County jail on suspicion of third-degree driving under the influence and child endangerment. The Minnesota Star Tribune generally does not identify suspects before they are charged.

Court records in western Wisconsin show that the man has a drunken driving case pending from a traffic stop in December. Allegedly, his blood alcohol content was 0.15%, nearly twice the legal limit, and he had a passenger under 16 years old with him.

Also, the man was not licensed to drive a school bus, state Department of Public Safety spokesman Mark Karstedt said, because he failed the required BCA background check.

The man was driving a bus that is operated by the Big River Bus Company in Hastings, said Principal Todd Herber.

Big River's chief operating officer, Thomas Severson, released a statement that read, "The driver's alleged behavior is a complete violation of our company policies, values and commitment to student safety. The driver as well as the bus aide who failed to report the incident have been terminated."

Late Thursday, Severson pushed back on the state saying the man should not have been operating the bus. "He presented a valid temporary license with passenger and school bus endorsements," Severson said.

Severson said Big River hired the man on Dec. 3 after passing a pre-employment background check, and drug and alcohol screening. That's before he was charged with drunken driving in Wisconsin.

Principal Todd Herber explained in a letter to families that "while one of our staff members was helping students board a school bus ... they noticed that the bus driver appeared to be impaired."

Herber said the students were immediately removed from the bus, before the driver's arrest.

"I appreciate the quick response of our staff in recognizing that something didn't seem right with the bus driver," the principal added.