Scott Blackwood, 30, was battered, stabbed, stamped on, strangled and tied to a bath before an attempt was made to set him on fire.
Allan Nicol, 36, and Thomas Moore, 26, and Georgina Smith, 22, unleashed their sickening violence on Mr Blackwood despite claiming to be his friends.
Nicol and Moore were found guilty of murdering Mr Blackwood at Wheatley Road, Saltcoats, Ayrshire last July 3 or 4. They were both sentenced to life imprisonment and ordered to serve at least 20 years each before being eligible for parole.
Judge Lord McEwan said: "This was a scandalous, disgraceful and horrific attack on a young man, including what amounted to torture."
Smith, 22, was convicted of the lesser charge of culpable homicide following a five-week trial at the High Court in Glasgow. She will be sentenced next month.
The court heard Mr Blackwood was relentlessly bullied by the mob before he was brutally set upon last July.
The attack began in Nicol's home. Mr Blackwood was then dragged half dead to his own home just a few doors down the street.
There he was taken to the bathroom and tied to the bath with a ligature and had turpentine poured over him.
Some of the horrific injuries were inflicted as he lay dead or dying.
The trial heard that punches, stamps and kicks rained down on him and he was struck with a piece of wood, a metal bar and a knife.
Mr Blackwood was then strangled with a tie, tied by the neck to a bath, bound by his ankles with a dog lead, and white spirit was poured over him and set on fire.
The court was told Mr Blackwood suffered 72 separate injuries. He suffered 13 stab wounds and three broken ribs. His eye socket and cheekbones were smashed.