Questioned by Common Pleas Court Judge Jeffrey P. Minehart, all three - Will "Pooh" Hook, 43, also known as Keith Epps, the alleged mastermind of the robbery-turned-murder, and alleged gunmen Edward Daniels, 44, and Antonio Wright, 30 - said they would not testify in their defense.
If the defense lawyers do not present evidence - as is their constitutional right - the trial could move to closing arguments.
All three men are on trial for felony murder in the June 27, 2009, slayings of Thal and friend Timothy Gilmore, 40, outside her apartment in the then-new Piazza complex in Northern Liberties.
Four out of the eight people arrested in the incident have pleaded guilty; one defendant, arrested a year after the shootings, will be tried separately later.
Prosecutors say the gunmen confronted Thal, a party planner, and Gilmore, an Ohio-based long-distance trucker, both of whom were also involved in the city's drug trade.
Gilmore tried to flee, and the gunmen opened fire, killing both. The gunmen then fled, leaving behind what they came for: more than $100,000 in cash and 81/2 pounds of cocaine that police later found in Thal's apartment.
Gilmore's death was captured by a Piazza security camera near the elevators on the seventh floor of the Navona building. But Thal's was not, and the circumstances of her death - and whether she was an active participant in Hook's alleged drug robbery scheme - remain at issue.
The only account of Thal's death has come in two statements by admitted gunman Donnell Murchison, 35, who pleaded guilty to two counts of murder to escape the death penalty. The statements were read to the jury Friday by Vega but were then stricken from the jury's consideration by Minehart after Murchison refused to answer defense questions, as required by his plea deal.
Murchison's statements contend that Thal was in on Hook's robbery scheme and was supposed to get a cut of the cash and drugs later found by police in her apartment after the slayings.
According to Murchison, when he, Daniels, and Wright confronted Thal and Gilmore in the hallway, Daniels grabbed Thal from behind and put a gun to her head while he pointed his gun at Gilmore.
Gilmore began to resist, shooting began, and Murchison said he saw Thal fall to the floor. Murchison said he did not see Thal get shot but assumed she was hit in the eruption of gunfire.
Collins, however, said the tears in the skin around the entrance wound in the back right side of her head were a "classic sign" of a contact gunshot wound. Collins said the bullet traveled down and forward through Thal's brain and exited on the left side of her neck, above the collarbone, and was likely instantly fatal.
Collins also testified that tests on Thal's blood showed the presence of Xanax, a prescription antianxiety drug, as well as amphetamines and methamphetamines.
Contact staff writer Joseph A. Slobodzian at 215-854-2985, firstname.lastname@example.org, or @joeslobo on Twitter.