VANCOUVER -- The Metro Vancouver Transit Police have arrested a man who is suspected of committing two sexual assaults while riding on public transit.

In the most recent incident at 7:15 a.m. on Dec. 3, transit police say a young woman boarded a SkyTrain car at Nanaimo Station. It was standing room only and as the train approached Commercial-Broadway Station, she felt a hand grope her buttocks several times.

She looked at the man next to her and saw his hand near the spot where she had been touched, and then asked another passenger to push the onboard alarm for her.

When the train arrived at Commercial-Broadway, both the young woman and the suspect got off and the woman immediately spoke to an attendant and pointed out the suspect, according to transit police.

Officers on patrol at the station searched for the suspect and found him on a pedestrian overpass and arrested him. They determined that Grant Lionel Houle, 39, had another warrant out for his arrest for a previous sexual assault on a bus in June.

Houle has now been charged with sexual assault, in relation to the latest incident in December.

In late November, police and Vancouver's nightclub industry launched an advertising campaign called "Hands Off!" to make it clear that unwanted sexual touching is a form of sexual assault.

In Vancouver, police have investigated 174 incidents of unwanted sexual touching since the beginning of 2018, and an additional 75 incidents have been reported to transit police.

"The numbers are high and it's a concern for us, so now is the time to get this messaging out and to encourage people to stop this behaviour. It's unacceptable," said Sgt. Steve Addison, an officer with the Vancouver Police Department, when the campaign was launched on Nov. 26.

The VPD and Metro Vancouver Transit Police say they want both victims and perpetrators to know that unwanted sexual touching – groping – will be taken seriously by police, and they want victims to report all incidents to police.

"It's a criminal act," said Sgt. Clint Hampton, a spokesperson for the Metro Vancouver Transit Police.

"Be on notice. If you touch someone inappropriately, if you grope someone, we will come after you. We will complete a thorough investigation and we will arrest you. Hands off."

With files from CTV News Vancouver's Shannon Paterson.