A 17-year-old stabbed a schoolmate Tuesday inside a high school classroom in Baltimore, leaving the other teen with life-threatening injuries, police said.

The 10th-grader went into an occupied third-floor classroom at Renaissance Academy High School about noon, said T.J. Smith, a spokesman for the Baltimore Police Department. The youth stabbed a 17-year-old 11th-grader and ran away, Smith said.

Witnesses were able to give police a good description of the suspect, and he was arrested shortly after the stabbing near his home, the spokesman said. Smith would not say if the knife used in the attack had been recovered.

The victim was taken to a hospital, Smith said. No one else was hurt, and the school was evacuated.

It was not known what led to the stabbing, Smith said.

Public schools Police Chief Marshall Goodwin said a school resource officer rotates among Renaissance Academy and other nearby schools. His department conducts safety checks at the school, and he said metal detectors are on hand. Goodwin said investigators are trying to determine how the student got a knife into the school.

Gregory Thornton, Baltimore Public Schools CEO, said classes will not be conducted at Renaissance Academy on Wednesday, but students will be sent to another site.

The Baltimore Sun reports that a student at the school was taken into custody last week after bringing a loaded handgun into the school.

Renaissance Academy was founded in 2005 and moved to its current location a year later, according to its website. It offers a college prep curriculum.