Additional charges regarding a second victim have been brought against a former Marlborough School teacher.

Joseph Koetters, 47, pleaded not guilty on Monday to 10 additional charges regarding alleged sexual abuse of a second former student. In February, he pleaded not guilty to four charges regarding a first victim.

The English teacher and Santa Monica resident worked at Marlborough, an all-girls school for grades 7-12 located at 250 S. Rossmore Ave, from 1999 to 2013.

The Los Angeles District Attorney’s Office said Koetters allegedly initiated a sexual relationship for more than a year with the first victim, then a 16-year-old female student, starting in 2000. In February, he was charged with two counts of oral copulation of a person under 18 and two counts of sexual penetration by a foreign object of a person under 18.

The alleged crimes came to light last June when former Marlborough student Mikaela Gilbert-Lurie published an essay on www.xojane.com, titled “It Happened To Me: My High School English Teacher Told Me He Loved Me (And Nobody Did Anything)”.

Gilbert-Lurie wrote about her experiences as a 16-year-old in 2012, when Koetters was her teacher, which detailed inappropriate moments between the teacher and the student, including Koetters brushing his hands against her knee.

The 10 new counts (five counts of oral copulation of a person under 18 and five counts of sexual penetration by a foreign object of a person under 18) stem from a second victim who reported the incident to police as the first case remained under investigation. According to the district attorney’s office, the second victim was 16 when she had a sexual relationship with Koetters between February and June of 2004.

Koetters was released in February on $140,000 bail, but the new charges increased bail to $490,000. Koetters posted the complete bail on Monday and was released again, but he is not allowed to contact the two victims. He is scheduled to return to the Foltz Criminal Justice Center, Department 31, on June 23 to set a date for a preliminary hearing.

If Koetters is convicted, he faces more than 11 years in state prison. Police continue to investigate the case.

The victim of the first charges reported the incident to police last July after she read Gilbert-Luri’s online essay. She is represented by attorney Dave Ring in a civil suit filed last month against Koetters and the school, which accuses Marlborough of ignoring past allegations of wrongdoing by the teacher.

Ring said that Koetters groomed and conditioned the girl into having a sexual relationship with him, and impregnated her while she was a senior in high school.

“Mr. Koetters preyed upon his students to sexually gratify himself over the years he taught at Marlborough,” Ring said earlier this year. “The school knew of his misconduct and tried to sweep it all under the rug. They did nothing to protect their students and should be equally blamed.”

Last November, Marlborough head of school Barbara Wagner announced she would be stepping down at the end of the academic year.

The announcement followed an investigation into the past alleged misconduct of Koetters.

The Marlborough Board of Trustees formed a special investigative committee when it learned about the situation, and the board changed its school guidelines based on recommendations by the committee.

The committee found that during the years he was at Marlborough, Koetters did attempt to engage students in improper conduct, but at the time, he was only required to attend counseling.

“Given that Koetters’ actions are currently subject to both criminal and civil litigation, it would be inappropriate to comment further at this time,” Marlborough School officials said in a statement.