An off-duty San Jose police sergeant aboard a BART train with his fiance to get their marriage license detained an Oakland woman for allegedly trying to rob passengers, San Jose police said.

San Jose police Sgt. Fredrick Kotto was inside a BART train near Oakland en route to San Francisco with his bride-to-be at about 10:25 a.m. on Feb. 11, police said.

Kotto then heard a commotion behind him and saw several people in a physical altercation and heard someone shout "Stop him! He tried to rob me," police said.

When Kotto went to investigate, people were yelling for someone to call the police and he observed the suspect standing on a seat and pushing other passengers in an attempt to escape, police said.

One of the passengers tried to subdue the suspect with a stun gun weapon but failed, police said.

Kotto, concerned that the suspect might escape, blocked her path, raised his shirt to display his police badge and off-duty gun and ordered the suspect to the floor.

The suspect did not cooperate after Kotto grabbed her arm and appeared to be trying to get away so he pulled her down to the floor, held her wrists together and got her to calm down, police said.

When the train pulled into the West Oakland station, BART police officers boarded and took the suspect into custody as the crowd of passengers cheered Kotto and the officers, police said.

Kotto asked BART officers if he could make a statement about the incident later so he and his fianci could continue to their appointment to obtain their marriage license and the officers agreed, according to police.

He and his fianci were able to make their appointment several minutes early, police said.

Kotto, an internal affairs investigator, later telephoned BART police detectives to provide his account of what happened with the suspect, police said.

The Alameda County District Attorney's Office charged the suspect, Jennifer Davis, 31, of Oakland, with one count of robbery and her probation from a previous conviction was revoked, police said.