BOSTON (AP) — Winchester police brought stabbing suspect Jeffrey Yao to the hospital for psychological evaluations many times before he allegedly stabbed a woman to death in the town library.

The Boston Globe reports police documents chronicle Yao's two dozen run-ins with police over the course of six years.

Twenty-three-year-old Yao is being held without bail after pleading not guilty last month to allegedly killing Deane Kenny Stryker on Feb. 24 with a 10-inch knife.

Yao's attorney J.W. Carney Jr. has said Yao's chronic mental illness played a role in the attack. Police reports show Yao's behavior was first reported in 2012, when he posted shooting-related materials online. A child psychiatrist evaluated Yao and found him to not be a threat to others.

Yao will return to court April 11.