Montgomery County prosecutors asked a judge yesterday to dismiss charges against a Potomac man suspected of killing his mother, a reversal that came one day before they were scheduled to present their case against him to a grand jury.

District Court Judge Michael J. Algeo dismissed the first-degree murder and robbery charges during an afternoon hearing. Mark K. Makki had been accused of beating and strangling his mother, Shohreh Seyed-Makki, on Oct. 6 in their Potomac home. Neither Makki nor his attorney was present.

"During the three weeks since the arrest, the investigation has not developed sufficient evidence to seek an indictment by the grand jury or to continue the charges against Mr. Makki," John McLane, a spokesman for the state's attorney's office, said yesterday. "Accordingly, the charges against him were dismissed at this point."

The decision to drop the charges came after DNA samples from the crime scene showed that an unidentified man who is not Makki came into close contact with Seyed-Makki shortly before she was killed.

Makki learned that the charges had been dropped about two hours after the hearing as he was checking in with his parole officer near the Twinbrook Metro station.

"He was so happy he ran back inside to tell the [parole] officer: 'Hey, they dropped the charges!' " said his uncle, Farhad Makki, who was with him at the time. "He stayed in jail for four days. He didn't eat. He was in solitary confinement. The light was always on."

The decision to drop the charges will allow the family to start properly mourning the loss of Seyed-Makki, the uncle said.

"It has not yet sunk in what even happened," Farhad Makki said. "We were so busy trying to save one. Now everything is starting to click, and the emotions are going to run a lot higher."

Authorities declined to say yesterday whether investigators have solid leads on other suspects in the case. But a law enforcement source close to the investigation said Makki is still a suspect.

"This does not necessarily exonerate him," said the source, who declined to be identified because the case is open.

Makki's defense attorney, Bruce Marcus, declined yesterday to assess the police investigation that led to his client's arrest, saying he has had minimal access to the evidence. Makki declined to comment through his attorney.

"He's obviously relieved," Marcus said. "We're pleased that the investigation will continue. Hopefully police will find the perpetrator."

A Montgomery police spokesman defended the department's investigation.

"We feel that there was enough evidence at the time to arrest and charge him," said Lt. Eric Burnett. "We felt we had enough probable cause. We still feel confident about what we did at the time when he was arrested."

Burnett declined to say whether police and prosecutors clashed over the decision to drop the charges.

But he noted: "We didn't drop the charges; we had no control over whether or not the charges were dropped. It was the state's attorney's decision to drop the charges. They chose to drop the charges. We respect that decision."

Makki, 23, was arrested three days after the slaying. A homicide detective said in a charging document that Makki lied to investigators about his whereabouts at the time of the killing, had an unexplained fresh wound and was carrying an envelope believed to have held his mother's money.

At the time of the arrest, police noted that Makki and his mother often clashed over his relationship with his girlfriend, Aramis Mizani. Burnett said he could not comment on whether the relationship is still a possible motive or a focus of the investigation.

Makki was denied bond during an Oct. 11 preliminary hearing, during which prosecutors said they feared that if he were to be released, he could tamper with witnesses and evidence and flee the country, perhaps to Iran, his parents' native country. A prosecutor also said investigators collected a sample of what they believed to be blood from Makki's shoelaces.

Makki was released on $250,000 bond two days later, after prosecutors acknowledged that DNA tests conducted in the case did not link him to his mother's body at the time of the crime.

Makki had a preliminary hearing scheduled for tomorrow. Such hearings are seldom held, but they serve as deadlines by which prosecutors who have filed murder charges in District Court must seek grand jury indictments to transfer cases to Circuit Court.

The Makki family has proclaimed Mark Makki's innocence. Relatives have been critical of the police investigation and have said the arrest came as an unexpected blow to a family already distraught over the killing.

A relative who is close to Makki said the robbery charge was especially outlandish considering that Makki's parents made cash readily available to him. The relative asked not to be identified so as not to antagonize police.

The relative also said Makki might have lied to police when he was questioned because he habitually lied to his mother about his whereabouts to spend time with his girlfriend, whom his mother disliked.

Burnett said police hope their investigation will not be hindered by the family's reaction to Makki's arrest. He said the two leading homicide detectives in the case, Gary Turner and Dean Cates, remain at the helm of the investigation.

"I would hope that they would not have any ill feelings toward us," he said, referring to the Makki family. "At this time, we're not offering an apology. We have a person who has been murdered, and we're trying to close the homicide."

Mark K. Makki, 23, was accused of strangling his mother Oct. 6.