The case is on hold as prosecutors fight to enter into evidence an alleged confession in which Santiago supposedly bragged about being a cop-killer.
A Common Pleas Court judge hearing the case ruled during pretrial motions last week that the alleged admission could not be used. The DA's office filed an appeal on Tuesday.
The trial cannot continue until the Superior Court rules on the appeal.
``It's a letdown because you get yourself all geared up,'' said one of Trench's two daughters, Ann Marie Bachmayer. ``But if the appellate court rules in our favor, it's a crucial piece of evidence. We've been in this 13 years, what's another one?''
Santiago's lawyers said they and their client were disappointed that the trial had been delayed.
``Their pretrial appeal signals how weak their case is,'' said one of his lawyers, David Rudovsky. ``It makes you wonder about the rest of their case.''
The appeal centers on a statement Santiago allegedly made three years ago during a street fight in his Spring Garden neighborhood.
Santiago hit another man with a baseball bat and during the attack, allegedly bragged that he was a cop-killer, an apparent reference to the murder of Trench, an 11-year police veteran.
When Santiago pleaded guilty last year to the neighborhood assault, the prosecutor detailed the facts of the case. A judge asked Santiago if he agreed, and he did.
Rudovsky said Santiago had been pleading guilty only to the assault.
But one of the prosecutors on the murder case, Carlos Vega, said the admission showed that Santiago readily boasts about the kill.
The 13-year-old case has a complicated history that includes allegations of police and prosecutorial misconduct, and racial injustices against Latinos.
When Trench, 44, was killed in May 1985 in the Spring Garden section, police conducted illegal sweeps of the predominantly Latino neighborhood in their hunt for the killer.
Santiago, then 21, was picked up during the sweeps, but police held him for more than two months before they charged him with the crime.
The sweeps and the arrest outraged residents. They protested in the streets and sued the city.
Santiago was convicted the following year of first-degree murder, but the trial was riddled with allegations of prosecutorial misconduct.
As a result, a Common Pleas court judge overturned the conviction in 1992. Two years later, a Superior Court panel reinstated the charges and ordered a new trial.
The trial, which was scheduled to begin jury selection next week, will now be again postponed.