Charles Kennedy, the late Liberal Democrat leader, was subjected to vile social media abuse and vandalism in the three weeks running up to his death, according to a newspaper report.

The Scottish Daily Mail reported that Kennedy, who lost his parliamentary seat of Ross, Skye and Lochaber, on 7 May, returned home after election night to a nasty "welcome home" present.

"It was a Friday morning, when the rubbish gets taken out in and around Fort William," Kennedy's campaign manager, Conn O'Neill, told the paper. "When Charles got back to the cottage, he discovered his bins upturned and left at the end of his driveway. It seemed as if someone had gone through them and spread the contents everywhere."

Most of the social media abuse appeared to come from Scottish nationalists – or cybernats as they became known – because of his opposition to Scottish independence.

And most of it was focused on his well-known drink problems.

When Kennedy shared a tweet urging supporters to "display a poster in your window in support of Charles", a cybernat responded: "Just put an empty old whisky bottle in your window. It's the same thing."

On a Facebook chatroom for Scottish National Party supporters in Skye, one user said he should "get back in the pub". Another called him a "useless mess". On Kennedy's own Facebook page someone said he was "pished" and another said he'd been "on the drinky poos again".

A Twitter user whose profile carried an SNP logo, had dubbed him a "drunken alcoholic a**ehole", while another called him an "alkie c**t'.

One of Scotland's most senior Lib Dem officials told the paper: "I have never known aggression like it in 30 years of politics. He and his staff were shouted at on doorsteps, and had leaflets thrown in their face. But the worst of it happened online, where he was just monstered.

"It's a form of bullying that would not be tolerated in any playground. Charles tried to rise above it, but he couldn't always. It must have hurt."

The official himself declined to be identified because of fear of SNP cyberbullies and vandalism.