Danelo Cavalcante, 34, snuck past security at the Chester County Prison early on Thursday, Aug. 31, said West Chester police.
The convicted killer was last seen walking on Wawaset Road in Pocopson Township around 9:40 a.m., the District Attorney's Office said.
He is described as 5 feet tall and 120 pounds with brown eyes and "shaggy black curly hair." Cavalcante is a Brazilian national who speaks Spanish and Portuguese but only some English, and was last wearing a white T-shirt, gray shorts, and white shoes, they added.
Phoenixville police say he has ties to the borough and may be in the area.
Cavalcante is considered "extremely dangerous" and anyone who spots him should call 911, authorities said.
State police and Chesco detectives are conducting a "thorough county-wide search" Thursday afternoon, and prison staff will conduct an "internal investigation" into the escape, according to the DA.
US Marshals are also involved in the effort, authorities said at a press conference Thursday afternoon. Officials are offering a combined $10,000 in reward money for information that leads to the fugitive's capture.
Cavalcante was convicted on Aug. 16 of fatally stabbing his 33-year-old ex, Deborah Brandao, at her home in Schuylkill Township in April 2021, officials have said.
Prosecutors said he approached Brandao in front of her young children before he "grabbed (her) hair, threw her to the ground, and stabbed her 38 times in her heart, kidney, lungs, and liver, causing her to bleed to death."
He was sentenced to life in prison without the possibility of parole last Wednesday, Aug. 23.
Cavalcante is also a suspect in a 2017 murder in Brazil, the DA added.
Click here to follow Daily Voice Reading and receive free news updates.