Howard County prosecutors dropped all charges yesterday against Dimitrious (Jimmy) Prassos, who was charged in the robbery and slaying of his father, a popular Ellicott City restaurant owner, after a judge said some key evidence was inadmissible and indicated he might throw out part of the remaining case.

The start of the highly publicized trial came to an abrupt halt yesterday morning after prosecutors were left largely with hearsay evidence from two prison inmates and a former drug counselor alleging they were told that someone named Jimmy had plotted with a Towson man to rob a restaurant.

State's Attorney William R. Hymes said that withdrawing charges in a major felony case was unusual but he decided to drop murder, robbery and conspiracy counts against Prassos, 23, after Circuit Court Judge J. Thomas Nissel indicated Wednesday that he might retract some of his earlier rulings allowing some hearsay testimony at the trial.

"We didn't feel that in view of the totality of the evidence that we would be successful in our efforts to secure a conviction," Hymes said, adding that authorities may refile charges against Prassos if new evidence surfaces.

Prassos showed little emotion yesterday when prosecutors announced the decision. His mother, Kathy Angellides, who had been present at most court hearings, cried silently, while other relatives in the courtroom smiled and congratulated one another.

Afterwards, Joseph Fleischmann, the Ellicott City lawyer who represented Prassos, said he was pleased with the outcome. "A person should not be allowed to be convicted on hearsay evidence," he said.

Some lawyers said the prosecution was hampered by poor police investigation and weak circumstantial evidence.

Hymes defended the actions of the police and prosecutors in the case, saying the police were justified in arresting Prassos.

Prassos was charged with conspiring with William H. Ray Jr., 30, of Towson to arrange the robbery at the Pirate's Cove restaurant. Prassos' father, George Prassos, owned the restaurant and was killed there during the Aug. 2 robbery. Ray's trial is scheduled to start April 4. Prosecutors had no eyewitness to link Prassos to the robbery. Their key witness, Lisa Williams, 20, a waitress in a Towson restaurant, refused to testify, invoking her constitutional right against self-incrimination. She allegedly told police that she had seen Ray and the younger Prassos together with large amounts of money the day after the robbery.

The remaining evidence centered on hearsay testimony from two former cellmates of Ray's and a former drug counselor, Kathie McMillen, who treated Ray for drug addiction in Towson. Police testified at a pretrial hearing that they paid McMillen $360 to help move her to a new apartment as part of a deal to protect her and her family.

Police said they also had gathered evidence against Prassos indicating the robbery had been an inside job. For example, police said, the gunman knew exactly where the safe was and that the elder Prassos was the only one who could open it.

The prosecution's case appeared solid until early December, Hymes said, when Williams said she wanted to recant earlier statements implicating Prassos in the robbery. Prosecutors granted Williams immunity from prosecution in exchange for her testimony. She had identified Prassos in a police lineup and admitted to police at one point that she was the getaway driver in the robbery.

The case then started crumbling, Hymes said yesterday, hitting a low point Tuesday when Nissel ruled as inadmissible testimony from detectives about Williams' allegedly incriminating statements against Prassos.

Another factor in prosecutors' decision to drop charges against Prassos was concern that if he was acquitted at a trial, they could not refile charges against him because of his constitutional protection against double jeopardy, Hymes said.