A man is in hospital in critical condition after he was stabbed trying to sell his used cellphone to a buyer he found on Kijiji, say Calgary police.

The victim and his girlfriend went to the RBC parking lot in Shawnessey around 10:30 p.m. MT on Sunday to meet the person who had placed an ad in search of a used cellphone.

The victim got in the person’s vehicle and at some point the 21-year-old was stabbed in the chest, said Det. Torrey Killam.

Investigators believe there were three men in the vehicle, which fled the area, leaving the victim in the parking lot.

The victim’s girlfriend drove him to the South Health Campus emergency room. EMS crews then took the victim to the Foothills hospital in life-threatening condition, Killam said.

His condition has since been upgraded to serious but non-life-threatening.

3 men, Jeep sought

Police say they are looking for white mid-1990s Jeep and three black men.

Staff Sgt. Jim Stinson says police are doing an online investigation and hope to get some footage from security cameras in the parking lot.

"Lots of businesses in that area, so hopefully we're lucky with the CCTV," he said.

A Kijiji spokesperson said in a statement that they have been in touch with Calgary police and they recommend all users follow a few simple rules.

All transactions should be done in person.

Never send money electronically.

If something sounds too good to be true, it likely is.

Meet in a public place with many people around, such as a coffee shop.

Anyone with information about the incident is asked to call police or Crime Stoppers.

Police are reminding the public to take precautions when meeting people to buy or sell goods: