(CBS/AP)-- A Massachusetts high school teacher allegedly killed by a student last week comforted others and was devoted to her vocation, "focusing on the adults of the future," a relative said Monday at her funeral, where many of the hundreds of mourners who packed the church wore her favorite color, pink.
Colleen Ritzer, 24, who taught math at Danvers High School, was killed in a school bathroom after dismissal Tuesday, police said. Her body was found in woods behind the school. Philip Chism, 14, has pleaded not guilty to a murder charge.
St. Augustine Church in Ritzer's hometown of Andover was filled to capacity for her funeral Mass, including about 400 students who arrived in buses. Many mourners wore pink ribbons or scarves and bouquets of pink flowers were placed on the steps of the church. Pink was Ritzer's favorite color, friends said.
"She made people feel loved, comforted and optimistic. Colleen's grace made her life fulfilling," said Ritzer's cousin, Gina McDaniel, in a eulogy prepared for delivery at the service. "In such a short period of time, one person has made a world of difference.
"Your memory will live on forever in the hearts of everyone you touched as a teacher, daughter, sister, granddaughter, niece, cousin and friend. Heaven stole an angel from us today. You will always be in our hearts, we love you, rest in peace," McDaniel said, according to CBS Boston.
Ritzer's passion was teaching, and she was able to make many students enthusiastic about math, even those who did not like the subject at first, said McDaniel, adding that her cousin "wanted to make this world a better place by focusing on the adults of our future."
Teachers from Danvers and Andover lined the steps of St. Augustine as Ritzer's coffin arrived at the church for the private funeral.
"In the face of great tragedy, we are shocked and horrified," the Rev. Peter Gori said in prepared remarks for his homily. "We are naturally inclined to ask why. It is immensely frustrating when, like now, there is no satisfactory answer to that question. This makes it hurt even more."
Authorities have not spoken of a possible motive in the case. A classmate who was in Ritzer's last-period Algebra I class with Chism said the teacher had asked Chism to stay after class Tuesday. Another classmate said she saw Ritzer and Chism in the classroom after school, shortly before Ritzer was killed.
Chism's mother, Diana, is heartbroken for Ritzer's family, according to a statement released by Chism's public defender. The boy had moved to Massachusetts from Tennessee before the start of the school year and played on the school's junior varsity soccer team.
Ritzer, though her life was cut short, made a great impact on those around her, Gori said.
"Twenty-four years is not a very long time by anyone's measurement. And yet, in that time that was hers, she showed herself to be a beloved daughter and granddaughter, a delightful sister, niece and cousin, a really good friend and student, and not least of all, a truly wonderful teacher," he said.
Ritzer's family has established a memorial scholarship fund to benefit Andover High School graduates who also pursue teaching careers.