A man found guilty of brutally assaulting four women in Montreal has lost his attempt to have his convictions overturned.

The Quebec Court of Appeal said that DNA evidence collected from a cup of coffee left at a restaurant does not violate the right to privacy.

Giovanni D'Amico was found guilty in 2014 on multiple counts of sexual assault, one charge of sexual assault causing bodily harm, and one count of assault.

The attacks occurred between 2002 and 2005, but D'Amico was only arrested in 2008 after DNA testing linked him to the crimes.

The trial took more than four years and several victims were reluctant to co-operate with police, while one of them died before she could testify.

The NDG businessman was convicted in 2014 and sentenced a year later to 12 years in prison.

D'Amico appealed the verdict with his lawyer arguing that the collection of DNA did not take place appropriately.

In its ruling the court said that manner of collection was appropriate and the conviction would stand.

However the court said the process raises another question that society and the legislature should analyze: Should police be able to collect DNA from suspects, and how long should they be allowed to keep samples?