Five months after the stabbing death of Winnipeg bus driver Irvine Fraser, police are investigating an online death threat toward a driver.

On Thursday, someone posted this on Twitter to Winnipeg Transit:

"My bus is 20 minutes late every single day I will murder the driver next time just a heads up"

"Obviously wasn't impressed nor were my members I mean with the climate out there, something like that to come through," said Amalgamated Transit Union President John Callahan.

The threat isn't the only issue that's upsetting bus drivers. A response on Twitter from the city is drawing fire as well.

311 replied back with this message thanking the person:

"Thanks for reaching out, we would like to investigate your concern. We have sent you a DM requesting info. Please check at your leisure"

"It went through the membership again I'll say like wildfire," said Callahan.

Callahan notified the city councillor who oversees transit, Marty Morantz.

"The response was an unfortunate response," said Morantz. Morantz said he in turn informed the deputy chief of police.

The incident has spawned a new protocol to ensure this doesn't happen again. Threats on Twitter must be immediately reported to police by 311.

"I can tell you this is the very first time that Winnipeg's 311 service has received a threatening text like this, I'm advised that it has not happened before," Said Morantz.

The Winnipeg Police Service says the person's intent is unknown but it's taking the Twitter threat seriously. It stresses a threat online can lead to charges.

"It is a criminal offence, utter threats to cause harm or death and that's one thing we’re going to look at here if we can substantiate that charge here," said Const. Jay Murray.

The city and police said the threat was made by a Winnipeg resident. Police believe a female made the post.