RCMP have arrested a Halifax-area teacher accused of assault and mischief after an Oct. 3 incident involving a student.

Derek William Stephenson, an English teacher at Cole Harbour District High School, was arrested Nov. 9 and is scheduled to appear in Dartmouth provincial court on Dec. 12, RCMP said in a news release Tuesday. No charges have yet been laid.

Stephenson is currently on administrative leave and has voluntarily surrendered his teaching licence, the Halifax Regional Centre for Education said in a statement today.

"An altercation occurred when the man removed ear buds from a 15-year-old youth's ears," the RCMP release says. "The youth then removed the man's lanyard that was attached to keys in his pants pocket. The man then pushed the youth into a wall, and put him on the floor."

The boy reported the incident to the school administration. He was then checked by emergency health services, but wasn't found to have any injuries.

The RCMP were called to the school and investigated.

Reached by phone on Tuesday, Stephenson declined comment.

"I have been instructed not to speak to the media," he said. "Thank you very much."

Criminal history known by administrators

The administration at the Halifax-area high school knew that Stephenson had a criminal history involving threats and domestic violence, and had vouched for his character with justice officials following at least one of his earlier encounters with the law.

The Oct. 3 incident happened in a classroom, and a four-second video recorded by another student has been circulating on the social media app Snapchat, where a man is seen kneeling and briefly putting a student in a choke hold.

The latest incident is raising questions about what Halifax-area education officials beyond the school knew of the criminal charges Stephenson previously faced while he was a teacher, and what measures, if any, were taken.

That past includes pleading guilty in October 2017 to threatening his ex-girlfriend, who is a teacher at another school, and a November 2013 guilty plea for assaulting his ex-wife, a case in which a charge of assaulting his daughter was withdrawn. In 2010, a woman also got an emergency protection order against him.

Derek William Stephenson, an English teacher at Cole Harbour District High School, is shown in this 2012 image from a CBC story about a school rap performance. On Nov. 9, he was arrested and is scheduled to appear in Dartmouth provincial court next month following an altercation with a student in the classroom. (CBC)

Nancy Jakeman, a former member of the Halifax Regional School Board, said elected members were never told about those cases. It's something that now strikes her as an unsettling lack of transparency and accountability, given board members were typically informed when other teachers faced charges.

"It definitely bothers me," Jakeman said in an interview. "It raises concerns. The fact that it wasn't brought forth to the board, I just don't agree with that, I think that it should have been."

It also doesn't sit well with the family of the 15-year-old student Stephenson is accused of assaulting. The student's older brother said in an interview that the teen told him the incident started after Stephenson ripped out the student's earphones.

The older brother, who is an adult and was not present, said his younger brother told him he then touched Stephenson's lanyard. The teacher began to taunt the teen, he said, and then "charged at him and tackled him," shoving the boy against the wall.

"If you have somebody that has assault charges and then you let them work at the school and then they assault somebody again, that's really a bad decision on their part," the older brother said of school officials.

CBC News has decided not to identify the student due to his age. The assault allegation has not been proven in court.

While Stephenson has previously been found guilty of crimes, court documents and audio recordings of past court proceedings show how glowing references, including at least one from a school administrator, have helped him avoid a criminal record.

In 2013, Stephenson was arrested outside Cole Harbour District High School and charged with assaulting his now ex-wife and their daughter at a Dartmouth, N.S., home.

He pleaded guilty that November to assaulting his wife; the court was told he grabbed her by the hair and pushed her. He was handed 18 months of probation and ordered to attend an intimate partner violence prevention program.

He received a conditional discharge, which meant he had been found guilty but would not have a criminal record after three years so long as he completed probation without a problem.

Vice-principal part of 'glowing' report for court

The then vice-principal at Cole Harbour High, Barrett Khan, provided a character reference for Stephenson's pre-sentence report, describing his creative dedication to working with students on initiatives, including producing videos, spoken word, musicals and building a haunted house.

Stephenson was arrested outside Cole Harbour District High School in 2013 and charged with assaulting his now ex-wife and their daughter at a Dartmouth, N.S., home. (Craig Paisley/CBC)

At sentencing, Crown and defence lawyers agreed the pre-sentence report, especially Khan's reference, led them to a joint-recommendation of a conditional discharge, because the assault appeared to be out of character.

Defence lawyer Geoff Newton highlighted to the judge Stephenson's work with students at the school and the "glowing nature of the pre-sentence report," arguing he should not be sent to jail. Crown prosecutor Perry Borden noted the "vice-principal at his school spoke very highly of him and his abilities."

Judge Alana Murphy granted Stephenson the discharge. She ordered a DNA sample be taken from him.

In court again, 4 years later

In October 2017, Stephenson also received a conditional discharge for mischief and threatening his ex-girlfriend. A charge of assaulting her was withdrawn. He was put on probation, and ordered to take anger management courses and to stay away from his ex-girlfriend.

Following his arrest on those charges, a fellow teacher at Cole Harbour, Peter Mahalik, acted as his surety to secure his release.

The Crown noted at sentencing a "positive pre-sentence report." He said Stephenson had been candid about his anger management problems and had "lost his temper in the course of a domestic dispute."

Defence lawyer Michelle James said it was in her client's "best interest to remain criminal-record free, given the nature of his employment."

In granting the conditional discharge, Judge Jean Whalen said: "If you're asked whether you've been found guilty of a criminal offence you have to say yes because I have to find you guilty before I impose sentence. If you're asked do you have a criminal record, you can say no because a conditional discharge is not a criminal record. What anybody does with that information, I have no control over, Mr. Stephenson."

Safety of students a priority: principal

Following the incident at the school last month, students in the classroom went to the school's office to report what happened, the boy's brother said.

In a message sent home from the school on the day of the incident, principal Dunovan Kalberlah said the staff member has been placed on leave pending the outcome of the investigation.

"The safety of our students is always a top priority," Kalberlah wrote.

Doug Hadley, Halifax Regional Centre for Education spokesperson, would not speak to the incident or to Stephenson's employment history, describing it as a "confidential, personnel matter."

The HRCE is responsible for administering the region's schools. It was created on April 1 after the provincial government dissolved all elected school boards in favour of an appointed advisory council.

Hadley would also not confirm if education officials received any reports about Stephenson's criminal history, or what action was taken in response.

"I can say that the HRCE takes any matter potentially impacting the safety and security of our students very seriously and we take all reasonable measures to ensure their safety is protected at all times while under our supervision," Hadley said in an email to CBC News last month.

Volunteers need regular police checks

School volunteers must clear a police background check and a check of the province's child abuse registry every three years, according to HRCE policy.

However, teachers only require a background check when hired, unless they break service longer than three months during the school year, according to the HRCE student protection policy.

Stephenson would not have passed a criminal-record check and a vulnerable-sector check until three years after pleading guilty, according to Const. John MacLeod, a Halifax Regional Police spokesperson.

After being hired, if a teacher is under a criminal investigation, it is their duty to report that to the HRCE, said Hadley. There is no specific HRCE policy stating which crimes would be grounds for dismissal.

"If an employee was convicted of a crime, our human resources department would investigate the details of the conviction to determine if there is impact to them as an employee," said Hadley.

"Every situation is unique, and there are many factors which are considered when determining whether a criminal conviction would impact a person as an employee of the HRCE."