A San Francisco judge dismissed 26 more felony cases Friday involving plainclothes police officers who allegedly lied about the circumstances of drug searches and arrests or stole from suspects, bringing the number of prosecutions lost in the widening scandal to nearly 120.

Superior Court Judge Judge Cynthia Ming-mei Lee granted the dismissals at prosecutors' request. Outside court, prosecutors said the cases - nearly all of them involving drug charges - had been dropped largely because of potential credibility problems with an undercover officer at the Mission Station, Ricardo Guerrero, whose testimony in a preliminary hearing this year was called into question by videotape evidence that defense attorneys secured.

Prosecutors had already dropped eight cases in which Guerrero was involved since the video surfaced this month.

The video was of an arrest that Guerrero and other undercover officers from the Mission Station made at a Tenderloin residential hotel Dec. 30. It shows Guerrero carrying a gym bag from the suspect's room that he did not account for and was not booked as evidence.

Guerrero testified that he had removed only drugs and drug-related evidence from the room. However, the man who was arrested that day later said an iPod, a bottle of Tequila, 2 pounds of coffee, ball caps and T-shirts had disappeared from his room, and he suspected they were in the bag Guerrero carried out.

'Finally we got justice'

One case dropped Friday involved Harvey Salazar, 32, who had been held since March on drug charges. His mother, Mariette Tenorio, and stepfather, Javier Tenorio, said at a news conference that Guerrero and other Mission officers had stolen items from their home in August while conducting a search for evidence against Salazar.

The Tenorios filed a complaint about the search with the city's citizen-run police watchdog agency in February, before the wider scandal broke. In it, they said the Mission officers had taken two iPods, a camera, five ball caps, a jar of quarters and other items that police did not account for in their arrest reports.

"It's good - finally we got justice," Javier Tenorio said after Salazar was ordered freed Friday. "We will wait and see what happens about getting our stuff back."

Gascón's concerns

District Attorney George Gascón, who was police chief when the alleged misconduct occurred, said he felt it was his obligation to ask the court to dismiss cases involving the Mission unit.

"We are concerned that there were allegations that these officers were stealing property," Gascón said. "If we have officers that in fact are stealing property, that obviously ... puts into question their credibility in everything else that they do."

Gascón said he had referred the allegations about the Mission undercover unit to the FBI. The agency is already investigating allegations that undercover officers at Southern Station lied about the circumstances of searches that led to drug arrests.

Those allegations led prosecutors to drop 85 cases in March and April.

Gascón said that it was common for undercover officers to remove bags during searches without booking them as evidence. But he added, "Obviously, that is a bad practice."

Credibility seen as key

"Look, our entire criminal justice system rests on the credibility of the prosecution," Gascón said. "If you have people that are involved in the prosecution, whether it's an officer, whether it's an independent witness, whether it's a prosecutor, who is doing something that puts into question the credibility of the process, we need to stop and we need to make sure that does not occur."

The Police Department issued a statement saying it believes the cases could be revived if the undercover officers are cleared of wrongdoing.

If "any officer is proven to be dishonest, in any way, they will be disciplined," the statement said. "This discipline will be swift and severe, up to and including termination from the Police Department."

Guerrero, 45, a 17-year veteran, has been put on desk assignment, police say. Other members of the Mission unit have been reassigned to patrol duties.

"He's the common denominator on the cases dumped today," Public Defender Jeff Adachi said Friday of Guerrero.

Adachi released video from another case Friday that shows Guerrero approaching a man in the Tenderloin who was eventually arrested for allegedly dealing drugs. The police report of the arrest April 22, 2010 - written by another officer - said the man, Jesus Inastrilla, spit a $20 rock of crack cocaine into his hand as Guerrero approached, but the videotape doesn't show that.

Instead, the video - taken by a city-installed street camera - appears to show Inastrilla with a cell phone in one hand and his other hand in his pocket during the encounter.

Officer couldn't find drugs

The case was dismissed in May 2010 after Guerrero told prosecutors that he couldn't find the drugs that police allegedly had seized, Adachi said.

After prosecutors dropped the case, Inastrilla's lawyer filed a complaint against the officers. A spokesman for Police Chief Greg Suhr said Friday that the citizen-run Office of Citizen Complaints had upheld the complaint and sent it to Suhr for possible action.

"We have to find out if there was any wrongdoing," said Lt. Troy Dangerfield.

This story has been corrected since it appeared in print editions.