The two students who killed a total of 20 people in two separate school shootings in Finland over the past year probably knew each other, police have said.

Investigators said 22-year-old Matti Juhani Saari's rampage at his vocational school in the south-western town of Kauhajoki on Tuesday may have been modelled on another school shooting last November.

And police said the two killers were probably in contact before their shooting sprees.

'It's possible and I think that it's likely,' Jari Neulaniemi, who is heading up the investigation of the latest school shooting, has said.

'They had many interests and hobbies in common, like shooting, and shared the same ideas, the same thoughts,' he said. 'They were very much alike.'

Mr Saari, a culinary arts student, was dressed in black and wearing a ski mask when he went into his school and shot dead eight female students, one male classmate and a male teacher trapped inside a classroom.

He then set several fires in the building before turning his gun on himself.

Before his shooting, Mr Saari had posted a number of video clips on YouTube showing him shooting his semi-automatic .22 calibre handgun.

He had left behind two notes saying 'he hated mankind and the human race,' and 'I want to murder as many people as possible,' according to police.

There are similarities with the 7 November 2007 attack carried out by 18-year-old Pekka-Eric Auvinen.

He killed six students, a headmistress and a nurse before killing himself in a school in Jokela, north of Helsinki.

Mr Saari travelled more than 300km from Kauhajoki to buy his gun from a firearms dealer in Jokela.

The investigator would not confirm his gun had been bought from the same Jokela store where Mr Auvinen had purchased his .22-calibre weapon, but the small town only has one gun shop.

While investigators have yet to turn up evidence the two young men met in person or had phone or computer contact, they say they believe the contents of Mr Saari's computer could help establish the link.