Federal and local agencies have been searching for the 34-year-old convicted killer since he fled the Chester County Prison on Aug. 31.
During a press conference on Thursday, authorities said there was a possible sighting of Cavalcante just before 12 p.m. in the vicinity of Longwood Gardens.
"A search of that area has been underway for the past few hours and continues at this time," said Pennsylvania State Police Lt. Col. George Bivens.
TIMELINE: Everything we know about the prison break in Chester County
Cavalcante was spotted on Longwood Gardens' trail camera on Monday night. Bivens said the possible sighting on Thursday was not far from this location.
Investigators still believe he is within the search perimeter, which is about 8 to 10 square miles.
Authorities provide update on search for escaped murder convict as manhunt presses on for 8th day
Cavlacante changed from a nice neighbor to a jealous boyfriend, victim's sister says
The escaped prisoner was convicted of stabbing his former girlfriend, Deborah Brandao, 38 times in front of her two young children in Schuylkill Township in 2021.
The victim's sister, Sarah Brandao, told CNN that Cavlacante seemed to transform over time, eventually exuding jealousy and threatening Deborah before her death.
SEE ALSO: Fugitive Chester County killer used previous escapee's breakout methods: Warden
Sarah, who lived near both of them and is taking care of Deborah's two children and well as her own daughter in Pennsylvania, is terrified about his escape and worried that he could come after her.
"I haven't slept for many days. Since (his escape) I have been waking up with fright at night. I nap and wake up with fright," Sarah Brandao told CNN in an interview translated from Portuguese to English.
His behavior toward Deborah changed over time, Sarah said.
"She kept saying that he was extremely jealous - that when he drank, he became a different person; that he kept going through her cell phone," Sarah said.
Video captures escape
Video released by authorities on Wednesday shows how Cavalcante escaped prison.
It happened at 8:51 a.m. at the facility in Pocopson Township.
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The video shows Cavalcante walking toward a doorway at the Chester County Prison. He then spends a moment looking over his shoulder.
Video shows inmate's escape from Chester Co. Prison
Cavalcante then places his hands on one wall and his feet on another, then manages to scale the walls while parallel to the ground.
Acting Warden Howard Holland said Cavalcante was then able to climb up to the roof, push his way through razor wire, scale another fence, then push through more razor wire as he escaped.
Holland said there was a guard in the observation tower but that person did not see the escape.
We now know the officer in that tower is on administrative leave as a criminal investigation unfolds.
Timeline of Cavalcante's escape
Investigators say it took an hour for Cavalcante to be reported missing when he failed to report back from recreation time.
The following timeline was released by Acting Warden Howard Holland:
8:33 a.m.: Cavalcante's block entered the exercise yard
8:51 a.m.: Cavalcante escapes from the prison by crab-walking up a wall, pushing his way through razor wire, running across the roof and pushing his way through more razor wire
9:35 a.m.: Cavalcante's block returns to the unit from the yard
9:45 a.m.: Officers on Cavalcante's block notify central control of a missing inmate
9:48 a.m.: Officers inform central control that Cavalcante was missing. There was a belief he was in a phone visiting room but he was not there
9:50 a.m.: The prison was locked down and a special count was conducted
10:01 a.m.: The public escape siren was sounded and the 911 center was notified
Authorities provide update on search for escape inmate in Chester County
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Latest sightings of Cavalcante
Cavalcante has been spotted at least eight times since he escaped, said state police Lt. Col. George Bivens.
The most recent was at around noon, when a civilian saw someone who looked like Cavalcante running through an area near Longwood Gardens, one of the nation's premier botanical gardens. A trail surveillance video had captured Cavalcante walking through the garden's grounds on Monday night.
SEE ALSO: Pocopson Township resident believes escaped killer Danelo Cavalcante was in his home
On Tuesday night, state police say there was a sighting of Cavalcante by a resident in the area of Chandler Road in Pennsbury Township. Lt. Col. George Bivens said Wednesday that teams searched for hours but were unable to locate him.
Cavalcante was also spotted on video around 1:43 a.m. on September 2, on the 1800 block of Lenape Road in Pocopson Township. It's about 1.5 miles from the prison.
Police say Cavalcante was also spotted the next day from a distance by a state trooper who gave chase but lost him.
And hours before that, Ryan Drummond claims he saw Cavalcante inside his home on Friday night around 11:45 p.m. Police arrived but the man escaped back into the thick wood and brush after taking some food.
'I don't feel scared, but it's unsettling'
Wendy Hughes, 60, has resumed her morning walks but now carries pepper spray with her, and had the added comfort of seeing a state trooper in the neighborhood Thursday morning.
"I don't feel scared, but it's unsettling," said Hughes, who lives about 2 miles from Longwood Gardens. "You don't want to have to think about it anymore."
She works from her home in Chadds Ford, and hasn't needed to go out much. But other residents have dealt with roadblocks, intermittent lockdowns and school closures as sightings are reported.
"There's some frustration, but it's amazing on social media how critical people are. I'm thankful for the law enforcement officers. It's a tough job, in this heat, in the terrain around here," said Hughes, who heard a flurry of helicopter activity nearby just before midnight Wednesday. "Those conditions are probably wearing them down."
Targeted search area
Police have been shifting the perimeter of their search area since Cavalcante's escape to account for sightings and possible movements.
The borders of the current search are Route 926 to the north, Hillendale Road to the south, Creek Road to the east and Route 52 to the west.
Intense search for escaped Chester Co. prisoner continues
Hot weather, dense forest complicate search
Dense woods, thick underbrush and the hot weather in Chester County have been complicating the search for Cavalcante.
Pennsylvania state police addressed the issue after Cavalcante slipped the perimeter established by authorities after his escape from the county's prison.
Police said the brush is likely helping the convicted killer hide. Police say the brush is so thick that searchers can only go a few feet before losing sight of each other and they have to hack their way through it.
Devices usually used in searches like this are being hindered by the weather. It's too hot for technology that can spot body temperature to pick anything up.
Cavalcante has already gotten his hands on a backpack, clothing and unknown supplies.
Police say the convicted murderer is growing more desperate to get away and that they want to minimize the opportunity for him to encounter anyone else or obtain any additional items.
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What does Danelo Cavalcante look like?
Cavalcante is five feet tall and weighs 120 pounds with long, shaggy black curly hair and brown eyes. He is a Brazilian man who speaks Portuguese, Spanish and some English.
What was Cavalcante convicted of?
Cavalcante was convicted of first-degree murder on Aug. 16 for fatally stabbing his former girlfriend, Deborah Brandao, 38 times in front of her two young children in Schuylkill Township in 2021.
He was sentenced to life in prison without parole last week for the fatal stabbing and was set to be transferred to a state correctional institution in four weeks.
Prosecutors say he killed his girlfriend to stop her from telling police about the charges against him in Brazil. He was captured in Virginia after Brandao's killing and authorities believe he was trying to return to his home country.
How residents can help
Residents are being asked to secure their property, check on neighbors and keep an eye on security cameras. Call police if you see anything suspicious.
How to report Cavalcante info to police
Anyone with information is asked to call 911 or the U.S. Marshals' Tipline at 877-WANTED-2. There is a $20,000 reward for any information that leads to Cavalcante's capture.