A police SWAT team also cut power to the Lake View home of Dr. Timothy Jorden Jr., 49, a trauma surgeon at Erie County Medical Center where Jacqueline Wisniewski, 33, was shot to death earlier in the day. Lake View is a village about 17 miles south of Buffalo.
The shooting on the hospital grounds was "not a random act," The Buffalo News quoted unidentified officials as saying.
Jorden was described as a "person of interest" in the killing, the News said. Police were given photographs of the doctor and descriptions of four cars registered in his name.
Jorden has served in the Army and police said he may have had special weapons training.
The hospital was locked down for a few hours after the 8:15 a.m. shooting. Employees arriving for work were unable to get in, and emergency patients were taken to Buffalo General Hospital. The campus was reopened shortly before noon, the News said.
The newspaper said schools, including one where Wisniewski had a young son, also were locked down. The boy was picked up by his father, the News said.