Escaped prisoner Danelo Cavalcante was spotted twice Friday within the Chester County search area, Pennsylvania state police said, as officials appear to narrow in on the fugitive by reducing the search zone.

Authorities said these were “visual sightings” in the zone around Longwood Gardens, a public esplanade in the county. They did not provide further details. A new wanted poster was released Saturday.

Around 400 law enforcement officers from various agencies have assisted in the search. A perimeter of about 4 square miles was being searched Saturday, down from the roughly 10-mile perimeter they had on Friday.

Officers have used heat-sensing technology, K9 dogs and helicopters as they combed through portions of Chester County. Lt. Col. George Bivens with the Pennsylvania State Police said the search had been complicated by heat and high humidity, but officers “are up to the task.”

A reward of up to $20,000 is being offered for tips that lead to Cavalcante’s arrest.