This image shows CCTV footage of prison inmate Danelo Cavalcante looking around before escaping from Chester County prison on Aug. 31, 2023. Cavalcante received a life sentence last month for killing his ex-girlfriend in front of her children in 2021. He escaped while awaiting transfer to state prison. Chester County Prison via AP

WEST CHESTER — A prison tower guard has been fired after letting a murderer slip away on his watch in a brazen daytime escape, officials said Friday, as the nine-day-old search pressed on amid southeastern Philadelphia suburbs, farmland and a vast botanical garden.

News of the firing came as the searchers' ranks grew overnight, focusing on the area around Longwood Gardens, where the fugitive inmate has been spotted before.

Danelo Souza Cavalcante, 34, escaped while awaiting transfer to state prison on Aug. 31 after being sentenced to life in prison for fatally stabbing his ex-girlfriend in 2021. Prosecutors say he wanted to stop her from telling police that he's wanted over a killing in his home country of Brazil.

Authorities have described Cavalcante as extremely dangerous. With the search in its second week, nervous residents remain alert for any sign of him. Police believe Cavalcante has been spotted nine times since his escape, most recently on Thursday night, and has managed to get ahold of clothing and other supplies.

The Chester County Prison county guard was fired Thursday after 18 years as a corrections officer, county spokesperson Michelle Bjork said. He was on duty in the watchtower when Cavalcante scaled a wall by crab-walking up from the recreation yard, climbed over razor wire, ran across a roof and jumped to the ground.

Cavalcante's escape went undetected for more than an hour until guards took a head count. The guard, who was put on administrative leave after the escape, also had his personal cellphone on him at the time, a violation of jail protocol, Bjork said.

The spokesperson said she did not know the specific reason for the firing and could not give any more details about what the guard was doing when Cavalcante escaped.

County officials have said the watchtower guard should have seen Cavalcante trying to escape, but apparently did not, and they have not explained why he didn't see or stop Cavalcante, including whether he was on his cellphone and distracted.

Cavalcante has eluded hundreds of law enforcement personnel, including tracking dogs, tactical teams in full combat gear, and police on horseback and in helicopters southwest of Philadelphia.

On Friday, the ranks of searchers swelled to its largest number yet at around 400 personnel, Pennsylvania State Police Lt. Col. George Bivens told reporters at a command post.

Longwood Gardens was closed indefinitely after reports that Cavalcante may have once again been spotted on the property. People who remained there overnight Thursday were told to shelter in place as officers searched part of the garden.

The botanical garden, sprawling across nearly 200 acres, is normally open to the public with paths winding through gardens, an outdoor theater, ponds, fountains and meadows, with structures including indoor gardens, treehouses and a restaurant.

There was a possible sighting of Cavalcante on Thursday night that was being investigated, state police said, but further details were not disclosed. It came hours after another person reported seeing Cavalcante in another area of the vast botanical garden. On Monday night, a surveillance camera on a trail had captured him walking through its grounds.

There's now a $20,000 reward for information leading to his capture.

The escape and search have attracted international attention and became big news in Brazil. The main newspaper in Rio de Janeiro ran a lengthy story Wednesday with the headline “Dangerous hide-and-seek.”

Lt. Col George Vivens shows the map of the area delineated by law enforcement and their vehicles, during a media tour, at the Incident Command Center Where Pennsylvania State Troopers, U.S. Border Patrol, Chester County Emergency Management, and FBI are collaborating on the intergovernmental manhunt searching for escaped inmate Danelo Cavalcante, at the Po-Mar-Lin Fire Company, in Unionville, Pa. on Friday. Jessica Griffin/The Philadelphia Inquirer via AP

Jessica Griffin