Chief Prosecutor Raja Quereshi said the 20 witnesses already called, plus five who remain, are "sufficient for the prosecution to establish its case" against the chief suspect, British-born Ahmed Omar Saeed Sheikh, and three other defendants.
"The trial will conclude very soon," he said.
Quereshi's decision came as investigators sought to determine the identity of a body discovered in a shallow grave last Friday that is believed to be Pearl's. If it is — and if new suspects are charged as a result — Abdel Waheed Katpar, the main suspect's lawyer, has said the current trial must be thrown out and a new one started.
Dismembered remains, including a severed head, were dug up Friday near a blood-splattered shack where authorities believe Pearl was held. Police were led to the area by three new suspects, whom Pakistan television identified as members of a radical Muslim group, Lashkar-e-Janghvi, with links to al Qaeda.
Police have not formally charged them in the Pearl case, in part due to fears it would influence the current trial, said officials who requested anonymity. Karachi Police Chief Kamal Shah has even refused to say whether there were suspects in custody.
Quereshi would not comment on the possibility of new suspects being charged.
"A dead body has been found. It has yet to be determined whose dead body it is. Then one will have to see what is the outcome of the investigation as to whether there are any accused persons or not," he said.
Prosecutors and Pakistani officials have maintained that the investigation into the body would not affect the trial. Forensic experts obtained samples Monday from the remains to be used for DNA testing. Results are expected within a week.
An autopsy submitted to police indicated the victim was a white male whose neck had been cut and whose left hand was tied with green rope, a source close to the investigation said Monday.
Quereshi said he anticipates calling five more witnesses, including Pearl's widow, Mariane, possibly on Friday. Another witness is Arshad Noor Khan, the first judge who was removed because he was present during a Feb. 14 hearing where Saeed admitted his role in the kidnapping. Saeed later recanted.
Defense attorney Mohsin Imam said he believed the 13 witnesses were dropped because the prosecution is uncertain of their testimony.
The four defendants have pleaded innocent. The trial already has faced a number of delays since it began April 22 under heavy security in Karachi. The court was moved to Hyderabad after the prosecution raised fears of violence breaking out from the area's Muslim militants.
Quereshi has accused the defense of using delaying tactics, and two judges have already been removed.
Pearl, the Journal's South Asia bureau chief, disappeared four months ago in the restive port city of Karachi while researching a connection between Pakistani militants and Richard C. Reid, who was arrested in December on a flight from Paris to Miami with explosives in his shoes.
E-mails sent by Pearl's kidnappers were signed by the "National Movement for the Restoration of Pakistani Sovereignty," an unknown group that demanded better treatment for al Qaeda and Taliban fighters being held in Guantanamo.
A videotape of Pearl's slaying, delivered to U.S. officials on Feb. 21, showed the journalist's throat being cut with a knife.