BANGOR — A 21-year-old Bangor man was indicted Wednesday on one count each of intentional or knowing murder, kidnapping and gross sexual assault by the Penobscot County grand jury in the strangulation death of a Husson University student earlier this month.

An arraignment date for Zackery Mailloux has not been set.

Mailloux was arrested and charged with murder on Nov. 18 shortly after police discovered the body of Brooke Locke, 21, of Auburn at the Essex Street apartment the couple shared. The couple had recently broken up but still lived together, the court document said.

He is being held at Penobscot County Jail without bail.

The affidavit in the case was unsealed Wednesday after Mailloux was indicted. It said that Mailloux called Bangor police about 2 p.m. Nov. 18 to report he had strangled his ex-girlfriend at 166 Essex St. in Bangor.

He told police that he suspected Locke was cheating on him. Sometime after 7 a.m. on Nov. 18, he discovered a text message on Locke’s phone that confirmed his suspicion, according to the affidavit written by Bangor police Detective Tim Cotton.

Mailloux and Locke argued and he “manually strangled [her] to the point that he thought she was deceased,” according to the affidavit. “After a short time, Locke began to regain consciousness.”

He then bound Locke with wire cord and duct tape “for the entire morning,” the court document said. “During this incident, Locke admitted that she had been in another relationship.”

Mailloux also told police that he and Locke had sexual intercourse while she was bound.

After another argument, Mailloux said he used a necktie to strangle Locke until she no longer resisted.

A photo of Locke’s naked body, bound and gagged with duct tape on the bed in the bedroom Mailloux said they shared, was found on Mailloux’s phone, the affidavit said.

Cotton said Mailloux was “extremely calm and showed no emotion” when he arrived at the apartment.

A third-year occupational therapy student at Husson, Locke was a member of the Epsilon Tau Epsilon sorority. Her sorority sisters held a vigil Sunday night at Newman Gymnasium on campus.

More than 150 students, faculty, staff, alumni and community members attended the 45-minute service planned by Locke’s sorority sisters. Locke’s parents, Priscilla Locke of Auburn and Bill Locke of Darby, Mont., and other relatives attended the vigil but did not address the gathering.

Red, silver and black balloons adorned one end of the gym and posters displayed photos of Locke. Those who spoke described Locke as a young woman who was always smiling, eager to help others and hardworking.

Locke’s Edward Little High School classmates are holding a candlelight vigil near the school’s bell tower at 5 p.m. Wednesday, according to Cassandra Hartford, who along with 2010 class president Chris Camire has created the Facebook page “In Remembrance of Brooke Locke.”

If convicted, Mailloux faces between 25 years and life in prison on the murder charge.