Obadiah Whack is accused of shooting the 35-year-old mom of three through the door to her first-floor apartment at 628 North Law Street, APD said.
A bullet hole was found in her front door and a 9-millimeter cartridge casing was found on the hallway floor, according to authorities.
Trabal was taken to Lehigh Valley Hospital-Cedar Crest with a gunshot wound to the chest around 2 a.m. and died there hours later, the Coroner's Office has said.
Investigators said they spoke with witnesses who gave a description of the shooter and his license plate.
That led detectives to Whack, who was arrested at 315 N. 14th Street, APD said. He is being held at the Lehigh County Jail and also has an active arrest warrant out of Warren County, New Jersey.
Whack is charged with criminal homicide, prohibited possession of a firearm, and firing a gun into an occupied structure. His bail was denied at his arraignment on Wednesday, Oct. 4, court records show.
"Giselle was always a happy spirit and did the best she could given the circumstances of her life," her brother John Trabal wrote on a GoFundMe page.
"She lived a difficult life and was no stranger to hardship and throughout it all she made sure her kids were safe, cared for, and surrounded by love."
Her killing was the fifteenth recorded homicide in Allentown this year, and the twelfth deemed a "criminal homicide," APD noted.
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