Authorities were searching for Paris "Polerowski" Poe, 33, after sightings of the convicted felon in Verona, a city just outside of Madison, Wis., reports said.
About 1:47 p.m., the Verona Area School District enacted a "hard lockdown" for all its schools, with students only allowed to leave if parents or guardians with photo IDs picked them up, according to its website.
Buses were allowed to take students whose parents had not picked them up home as of about 3:30 p.m., according to the district's website, with an "increased police presence at all sites."
Poe was convicted of aggravated battery and robbery, and was released on parole in June 2011. His last known address is in 5900 block of South Indiana Avenue, officials said. He is wanted for questioning in a murder investigation.
Poe is described as 6 feet tall, 200 pounds and with black hair often worn in braids. He has many tattoos, including "Chief Hobo" on his upper right arm and "RIP Angie" on his upper left arm, officials said.
Poe is considered armed and dangerous, and anyone with information is asked to call 312-421-6700.
The FBI is offering a $20,000 reward for information leading to his capture.