Langley RCMP are investigating a brazen assault that started on a bus and finished with a suspect allegedly pulling a knife on a mother and her three children on Tuesday morning.

Police say that about 10:20 a.m. on a TransLink bus, a woman boarded and proceeded to get into an argument with the driver about paying her fare.

Other passengers, including a mother and her young children, complained about the woman’s profane language and asked her to stop swearing.

The suspect then threatened to kill both the mother and her children, eventually throwing a drink in the face of the youngest child, police allege.

Witness Darlene Henry told CTV News she overheard the suspect say: “I’m going to kill [your kids] and kill you and spit on their graves.”

Another witness caught the ensuing fight on camera. In it, the mother can be seen repeatedly punching the suspect who is lying on a seat. The suspect tries to kick out to defend herself from the onslaught.

The fight ended with the bus driver kicking both women off.

“It’s craziness, especially with the children involved,” said Cpl. Holly Marks. “I suppose I would understand a mother protecting her cubs if you will and where that all went. It’s just strange happenings we don’t see every day.”

Police say the mother and her children started walking towards a nearby mall, but the suspect followed and kicked one daughter, pushed over another and pulled out a knife.

RCMP arrested a woman 20 minutes after the ordeal at her home in Surrey. After being held in custody overnight, she appeared in provincial court Wednesday afternoon. Police are recommending charges of assault, assault with a weapon and uttering threats.

There is no word on what injuries the mother and her children may have sustained.

With a report from CTV Vancouver’s St. John Alexander